From: Ruben Kerkhof <ruben@rubenkerkhof.com>
Date: Fri, 8 Jun 2018 16:24:19 +0000 (+0200)
Subject: Merge pull request #2702 from elfiesmelfie/feat_snmp_agent
X-Git-Url: https://git.octo.it/?p=collectd.git;a=commitdiff_plain;h=e11b359144492baa97d648efc700203d0b56d32e;hp=0706e1c4c496962b92b7bd2149bb651ef05b0acf

Merge pull request #2702 from elfiesmelfie/feat_snmp_agent

snmp_agent: new features
---

diff --git a/Makefile.am b/Makefile.am
index 64414fbd..83b76a03 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1567,6 +1567,23 @@ snmp_agent_la_SOURCES = src/snmp_agent.c
 snmp_agent_la_CPPFLAGS = $(AM_CPPFLAGS) $(BUILD_WITH_LIBNETSNMPAGENT_CPPFLAGS)
 snmp_agent_la_LDFLAGS = $(PLUGIN_LDFLAGS) $(BUILD_WITH_LIBNETSNMPAGENT_LDFLAGS)
 snmp_agent_la_LIBADD = $(BUILD_WITH_LIBNETSNMPAGENT_LIBS)
+
+test_plugin_snmp_agent_SOURCES = src/snmp_agent_test.c \
+                                 src/daemon/utils_avltree.c \
+                                 src/daemon/utils_llist.c \
+                                 src/daemon/configfile.c \
+                                 src/daemon/types_list.c
+test_plugin_snmp_agent_CPPFLAGS = $(AM_CPPFLAGS) \
+	$(BUILD_WITH_LIBNETSNMPAGENT_CPPFLAGS)
+test_plugin_snmp_agent_LDFLAGS = $(PLUGIN_LDFLAGS) \
+	$(BUILD_WITH_LIBNETSNMPAGENT_LDFLAGS)
+test_plugin_snmp_agent_LDADD = liboconfig.la libplugin_mock.la \
+	$(BUILD_WITH_LIBNETSNMPAGENT_LIBS) $(BUILD_WITH_LIBNETSNMP_LIBS)
+
+check_PROGRAMS += test_plugin_snmp_agent
+TESTS += test_plugin_snmp_agent
+
+
 endif
 
 if BUILD_PLUGIN_STATSD
diff --git a/configure.ac b/configure.ac
index 1e31e218..eab34322 100644
--- a/configure.ac
+++ b/configure.ac
@@ -3814,7 +3814,7 @@ if test "x$with_libnetsnmp" = "xyes"; then
   LDFLAGS="$LDFLAGS $with_libnetsnmp_ldflags"
 
   AC_CHECK_LIB([netsnmp], [init_snmp],
-    [with_libnetsmp="yes"],
+    [with_libnetsnmp="yes"],
     [with_libnetsnmp="no (libnetsnmp not found)"]
   )
 
@@ -3822,6 +3822,62 @@ if test "x$with_libnetsnmp" = "xyes"; then
 fi
 
 if test "x$with_libnetsnmp" = "xyes"; then
+  SAVE_LDFLAGS="$LDFLAGS"
+  LDFLAGS="$LDFLAGS $with_libnetsnmp_ldflags"
+
+  AC_CHECK_LIB([netsnmp], [netsnmp_get_version],
+    [with_libnetsnmp="yes"],
+    [with_libnetsnmp="no (couldn't get libnetsnmp version)"]
+  )
+
+  LDFLAGS="$SAVE_LDFLAGS"
+fi
+
+if test "x$with_libnetsnmp" = "xyes"; then
+  SAVE_CPPFLAGS="$CPPFLAGS"
+  SAVE_LDFLAGS="$LDFLAGS"
+  SAVE_LIBS="$LIBS"
+  CPPFLAGS="$CPPFLAGS $with_libnetsnmp_cppflags -Wall -Werror"
+  LDFLAGS="$LDFLAGS $with_libnetsnmp_ldflags"
+  LIBS="$LIBS -lnetsnmp"
+
+  AC_CACHE_CHECK([whether netsnmp library has old API],
+    [c_cv_have_netsnmp_old_api],
+    [
+      AC_LINK_IFELSE(
+        [
+          AC_LANG_PROGRAM(
+            [[
+              #include <net-snmp/net-snmp-config.h>
+              #include <net-snmp/net-snmp-includes.h>
+            ]],
+            [[
+              netsnmp_variable_list *key = SNMP_MALLOC_TYPEDEF(netsnmp_variable_list);;
+              int val;
+              u_char type = ASN_INTEGER;
+              snmp_set_var_value(key, &val, sizeof(val));
+              snmp_set_var_typed_value(key, type, &val, sizeof(val));
+              return 0;
+            ]]
+          )
+        ],
+        [c_cv_have_netsnmp_old_api="no"],
+        [c_cv_have_netsnmp_old_api="yes"]
+      )
+    ]
+  )
+
+  if test "x$c_cv_have_netsnmp_old_api" = "xyes"; then
+    AC_DEFINE([HAVE_NETSNMP_OLD_API], [1],
+              ["Define 1 if you have old netsnmp API]")
+  fi
+
+  CPPFLAGS="$SAVE_CPPFLAGS"
+  LDFLAGS="$SAVE_LDFLAGS"
+  LIBS="$SAVE_LIBS"
+fi
+
+if test "x$with_libnetsnmp" = "xyes"; then
   BUILD_WITH_LIBNETSNMP_CPPFLAGS="$with_libnetsnmp_cppflags"
   BUILD_WITH_LIBNETSNMP_LDFLAGS="$with_libnetsnmp_ldflags"
   BUILD_WITH_LIBNETSNMP_LIBS="-lnetsnmp"
@@ -3832,7 +3888,7 @@ AC_SUBST([BUILD_WITH_LIBNETSNMP_LDFLAGS])
 AC_SUBST([BUILD_WITH_LIBNETSNMP_LIBS])
 # }}}
 
-# --with-libnetsmpagent {{{
+# --with-libnetsnmpagent {{{
 AC_ARG_WITH([libnetsnmpagent],
   [AS_HELP_STRING([--with-libnetsnmpagent@<:@=PREFIX@:>@], [Path to libnetsnmpagent.])],
   [
diff --git a/src/collectd.conf.in b/src/collectd.conf.in
index c2aa9152..6e22a7f2 100644
--- a/src/collectd.conf.in
+++ b/src/collectd.conf.in
@@ -1392,7 +1392,9 @@
 #    IndexOID "IF-MIB::ifIndex"
 #    SizeOID "IF-MIB::ifNumber"
 #    <Data "ifDescr">
-#      Instance true
+#      <IndexKey>
+#        Source "PluginInstance"
+#      </IndexKey>
 #      Plugin "interface"
 #      OIDs "IF-MIB::ifDescr"
 #    </Data>
diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod
index 69a1b1e0..6341574d 100644
--- a/src/collectd.conf.pod
+++ b/src/collectd.conf.pod
@@ -7791,7 +7791,9 @@ B<Synopsis:>
       IndexOID "IF-MIB::ifIndex"
       SizeOID "IF-MIB::ifNumber"
       <Data "ifDescr">
-        Instance true
+        <IndexKey>
+          Source "PluginInstance"
+        </IndexKey>
         Plugin "interface"
         OIDs "IF-MIB::ifDescr"
       </Data>
@@ -7802,12 +7804,44 @@ B<Synopsis:>
         OIDs "IF-MIB::ifInOctets" "IF-MIB::ifOutOctets"
       </Data>
     </Table>
+    <Table "CPUAffinityTable">
+      <Data "DomainName">
+        <IndexKey>
+          Source "PluginInstance"
+        </IndexKey>
+        Plugin "virt"
+        OIDs "LIBVIRT-HYPERVISOR-MIB::lvhAffinityDomainName"
+      </Data>
+      <Data "VCPU">
+        Plugin "virt"
+        <IndexKey>
+          Source "TypeInstance"
+          Regex "^vcpu_([0-9]{1,3})-cpu_[0-9]{1,3}$"
+          Group 1
+        </IndexKey>
+        OIDs "LIBVIRT-HYPERVISOR-MIB::lvhVCPUIndex"
+      </Data>
+      <Data "CPU">
+        Plugin "virt"
+        <IndexKey>
+          Source "TypeInstance"
+          Regex "^vcpu_[0-9]{1,3}-cpu_([0-9]{1,3})$"
+          Group 1
+        </IndexKey>
+        OIDs "LIBVIRT-HYPERVISOR-MIB::lvhCPUIndex"
+      </Data>
+      <Data "CPUAffinity">
+        Plugin "virt"
+        Type "cpu_affinity"
+        OIDs "LIBVIRT-HYPERVISOR-MIB::lvhCPUAffinity"
+      </Data>
+    </Table>
   </Plugin>
 
 There are two types of blocks that can be contained in the
 C<E<lt>PluginE<nbsp> snmp_agentE<gt>> block: B<Data> and B<Table>:
 
-=head3 The B<Data> block
+=head3 B<Data> block
 
 The B<Data> block defines a list OIDs that are to be handled. This block can
 define scalar or table OIDs. If B<Data> block is defined inside of B<Table>
@@ -7816,11 +7850,34 @@ The following options can be set:
 
 =over 4
 
-=item B<Instance> I<true|false>
+=item B<IndexKey> block
+
+B<IndexKey> block contains all data needed for proper index build of snmp table.
+In case more than
+one table B<Data> block has B<IndexKey> block present then multiple key index is
+built. If B<Data> block defines scalar data type B<IndexKey> has no effect and can
+be omitted.
+
+=over 8
 
-When B<Instance> is set to B<true>, the value for requested OID is copied from
-plugin instance field of corresponding collectd value. If B<Data> block defines
-scalar data type B<Instance> has no effect and can be omitted.
+=item B<Source> I<String>
+
+B<Source> can be set to one of the following values: "Hostname", "Plugin",
+"PluginInstance", "Type", "TypeInstance". This value indicates which field of
+corresponding collectd metric is taken as a SNMP table index.
+
+=item B<Regex> I<String>
+
+B<Regex> option can also be used to parse strings or numbers out of
+specific field. For example: type-instance field which is "vcpu1-cpu2" can be
+parsed into two numeric fields CPU = 2 and VCPU = 1 and can be later used
+as a table index.
+
+=item B<Group> I<Number>
+
+B<Group> number can be specified in case groups are used in regex.
+
+=back
 
 =item B<Plugin> I<String>
 
diff --git a/src/daemon/plugin_mock.c b/src/daemon/plugin_mock.c
index 8f8334ea..a11d4f54 100644
--- a/src/daemon/plugin_mock.c
+++ b/src/daemon/plugin_mock.c
@@ -56,7 +56,19 @@ int plugin_register_init(const char *name, plugin_init_cb callback) {
   return ENOTSUP;
 }
 
-int plugin_register_read(const char *name, int (*callback)(void)) {
+int plugin_register_read(__attribute__((unused)) const char *name,
+                         __attribute__((unused)) int (*callback)(void)) {
+  return ENOTSUP;
+}
+
+int plugin_register_write(__attribute__((unused)) const char *name,
+                          __attribute__((unused)) plugin_write_cb callback,
+                          __attribute__((unused)) user_data_t const *ud) {
+  return ENOTSUP;
+}
+
+int plugin_register_missing(const char *name, plugin_missing_cb callback,
+                            user_data_t const *ud) {
   return ENOTSUP;
 }
 
diff --git a/src/daemon/utils_cache_mock.c b/src/daemon/utils_cache_mock.c
index 5389d126..1495a803 100644
--- a/src/daemon/utils_cache_mock.c
+++ b/src/daemon/utils_cache_mock.c
@@ -24,8 +24,8 @@
  *   Florian octo Forster <octo at collectd.org>
  */
 
-#include <errno.h>
 #include "utils_cache.h"
+#include <errno.h>
 
 gauge_t *uc_get_rate(__attribute__((unused)) data_set_t const *ds,
                      __attribute__((unused)) value_list_t const *vl) {
@@ -41,3 +41,8 @@ int uc_get_rate_by_name(const char *name, gauge_t **ret_values,
 int uc_get_names(char ***ret_names, cdtime_t **ret_times, size_t *ret_number) {
   return ENOTSUP;
 }
+
+int uc_get_value_by_name(const char *name, value_t **ret_values,
+                         size_t *ret_values_num) {
+  return ENOTSUP;
+}
diff --git a/src/snmp_agent.c b/src/snmp_agent.c
index 0d1c5778..3c042a86 100644
--- a/src/snmp_agent.c
+++ b/src/snmp_agent.c
@@ -1,7 +1,7 @@
 /**
  * collectd - src/snmp_agent.c
  *
- * Copyright(c) 2017 Intel Corporation. All rights reserved.
+ * Copyright(c) 2017-2018 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
@@ -24,6 +24,7 @@
  * Authors:
  *   Roman Korynkevych <romanx.korynkevych@intel.com>
  *   Serhiy Pshyk <serhiyx.pshyk@intel.com>
+ *   Marcin Mozejko <marcinx.mozejko@intel.com>
  **/
 
 #include "collectd.h"
@@ -32,6 +33,7 @@
 #include "utils_avltree.h"
 #include "utils_cache.h"
 #include "utils_llist.h"
+#include <regex.h>
 
 #include <net-snmp/net-snmp-config.h>
 
@@ -40,12 +42,32 @@
 #include <net-snmp/agent/net-snmp-agent-includes.h>
 
 #define PLUGIN_NAME "snmp_agent"
-#define ERR_BUF_SIZE 1024
 #define TYPE_STRING -1
+#define GROUP_UNUSED -1
+#define OID_EXISTS 1
+#define MAX_KEY_SOURCES 5
+#define MAX_INDEX_KEYS 5
+#define MAX_MATCHES 5
+
+/* Identifies index key source */
+enum index_key_src_e {
+  INDEX_HOST = 0,
+  INDEX_PLUGIN,
+  INDEX_PLUGIN_INSTANCE,
+  INDEX_TYPE,
+  INDEX_TYPE_INSTANCE
+};
+typedef enum index_key_src_e index_key_src_t;
 
-#ifndef MIN
-#define MIN(x, y) ((x) < (y) ? (x) : (y))
-#endif
+struct index_key_s {
+  index_key_src_t source;
+  u_char type;
+  char *regex; /* Pattern used to parse index key source string */
+  int group;   /* If pattern gives more than one group we can specify which one
+                  we want to take */
+  regex_t regex_info;
+};
+typedef struct index_key_s index_key_t;
 
 struct oid_s {
   oid oid[MAX_OID_LEN];
@@ -54,6 +76,12 @@ struct oid_s {
 };
 typedef struct oid_s oid_t;
 
+struct token_s {
+  char *str;
+  netsnmp_variable_list *key; /* Points to succeeding key */
+};
+typedef struct token_s token_t;
+
 struct table_definition_s {
   char *name;
   oid_t index_oid;
@@ -61,6 +89,19 @@ struct table_definition_s {
   llist_t *columns;
   c_avl_tree_t *instance_index;
   c_avl_tree_t *index_instance;
+  c_avl_tree_t *instance_oids; /* Tells us how many OIDs registered for every
+                                  instance; */
+  index_key_t index_keys[MAX_INDEX_KEYS]; /* Stores information about what each
+                                             index key represents */
+  int index_keys_len;
+  netsnmp_variable_list *index_list_cont; /* Index key container used for
+                                             generating as well as parsing
+                                             OIDs, not thread-safe */
+  c_avl_tree_t *tokens[MAX_KEY_SOURCES];  /* Input string after regex execution
+                                             will be split into sepearate
+                                             tokens */
+
+  bool tokens_done; /* Set to true when all tokens are generated */
 };
 typedef struct table_definition_s table_definition_t;
 
@@ -71,7 +112,8 @@ struct data_definition_s {
   char *type;
   char *type_instance;
   const table_definition_t *table;
-  bool is_instance;
+  bool is_index_key; /* indicates if table column is an index key */
+  int index_key_pos; /* position in indexes list */
   oid_t *oids;
   size_t oids_len;
   double scale;
@@ -87,10 +129,13 @@ struct snmp_agent_ctx_s {
 
   llist_t *tables;
   llist_t *scalars;
+  c_avl_tree_t *registered_oids; /* AVL tree containing all registered OIDs */
 };
 typedef struct snmp_agent_ctx_s snmp_agent_ctx_t;
 
 static snmp_agent_ctx_t *g_agent;
+static const char *index_opts[MAX_KEY_SOURCES] = {
+    "Hostname", "Plugin", "PluginInstance", "Type", "TypeInstance"};
 
 #define CHECK_DD_TYPE(_dd, _p, _pi, _t, _ti)                                   \
   (_dd->plugin ? !strcmp(_dd->plugin, _p) : 0) &&                              \
@@ -105,6 +150,9 @@ static int snmp_agent_set_vardata(void *dst_buf, size_t *dst_buf_len,
                                   u_char asn_type, double scale, double shift,
                                   const void *value, size_t len, int type);
 static int snmp_agent_unregister_oid_index(oid_t *oid, int index);
+static int snmp_agent_update_instance_oids(c_avl_tree_t *tree, oid_t *index_oid,
+                                           int value);
+static int num_compare(const int *a, const int *b);
 
 static u_char snmp_agent_get_asn_type(oid *oid, size_t oid_len) {
   struct tree *node = get_tree(oid, oid_len, g_agent->tp);
@@ -131,10 +179,55 @@ static int snmp_agent_oid_to_string(char *buf, size_t buf_size,
   return strjoin(buf, buf_size, oid_str_ptr, o->oid_len, ".");
 }
 
-static void snmp_agent_dump_data(void) {
+/* Prints a configuration storing list. It handles both table columns list
+   and scalars list */
 #if COLLECT_DEBUG
+static void snmp_agent_dump_data(llist_t *list) {
   char oid_str[DATA_MAX_NAME_LEN];
+  for (llentry_t *de = llist_head(list); de != NULL; de = de->next) {
+    data_definition_t *dd = de->value;
+    table_definition_t const *td = dd->table;
 
+    if (dd->table != NULL)
+      DEBUG(PLUGIN_NAME ":   Column:");
+    else
+      DEBUG(PLUGIN_NAME ": Scalar:");
+
+    DEBUG(PLUGIN_NAME ":     Name: %s", dd->name);
+    if (dd->plugin)
+      DEBUG(PLUGIN_NAME ":     Plugin: %s", dd->plugin);
+    if (dd->plugin_instance)
+      DEBUG(PLUGIN_NAME ":     PluginInstance: %s", dd->plugin_instance);
+    if (dd->is_index_key) {
+      index_key_t const *index_key = &td->index_keys[dd->index_key_pos];
+
+      DEBUG(PLUGIN_NAME ":     IndexKey:");
+      DEBUG(PLUGIN_NAME ":       Source: %s", index_opts[index_key->source]);
+      DEBUG(PLUGIN_NAME ":       Type: %s",
+            (index_key->type == ASN_INTEGER) ? "Integer" : "String");
+      if (index_key->regex)
+        DEBUG(PLUGIN_NAME ":       Regex: %s", index_key->regex);
+      if (index_key->group != GROUP_UNUSED)
+        DEBUG(PLUGIN_NAME ":       Group: %d", index_key->group);
+    }
+    if (dd->type)
+      DEBUG(PLUGIN_NAME ":     Type: %s", dd->type);
+    if (dd->type_instance)
+      DEBUG(PLUGIN_NAME ":     TypeInstance: %s", dd->type_instance);
+    for (size_t i = 0; i < dd->oids_len; i++) {
+      snmp_agent_oid_to_string(oid_str, sizeof(oid_str), &dd->oids[i]);
+      DEBUG(PLUGIN_NAME ":     OID[%" PRIsz "]: %s", i, oid_str);
+    }
+    DEBUG(PLUGIN_NAME ":   Scale: %g", dd->scale);
+    DEBUG(PLUGIN_NAME ":   Shift: %g", dd->shift);
+  }
+}
+
+/* Prints parsed configuration */
+static void snmp_agent_dump_config(void) {
+  char oid_str[DATA_MAX_NAME_LEN];
+
+  /* Printing tables */
   for (llentry_t *te = llist_head(g_agent->tables); te != NULL; te = te->next) {
     table_definition_t *td = te->value;
 
@@ -149,62 +242,28 @@ static void snmp_agent_dump_data(void) {
       DEBUG(PLUGIN_NAME ":   SizeOID: %s", oid_str);
     }
 
-    for (llentry_t *de = llist_head(td->columns); de != NULL; de = de->next) {
-      data_definition_t *dd = de->value;
-
-      DEBUG(PLUGIN_NAME ":   Column:");
-      DEBUG(PLUGIN_NAME ":     Name: %s", dd->name);
-      if (dd->plugin)
-        DEBUG(PLUGIN_NAME ":     Plugin: %s", dd->plugin);
-      if (dd->plugin_instance)
-        DEBUG(PLUGIN_NAME ":     PluginInstance: %s", dd->plugin_instance);
-      if (dd->is_instance)
-        DEBUG(PLUGIN_NAME ":     Instance: true");
-      if (dd->type)
-        DEBUG(PLUGIN_NAME ":     Type: %s", dd->type);
-      if (dd->type_instance)
-        DEBUG(PLUGIN_NAME ":     TypeInstance: %s", dd->type_instance);
-      for (size_t i = 0; i < dd->oids_len; i++) {
-        snmp_agent_oid_to_string(oid_str, sizeof(oid_str), &dd->oids[i]);
-        DEBUG(PLUGIN_NAME ":     OID[%" PRIsz "]: %s", i, oid_str);
-      }
-      DEBUG(PLUGIN_NAME ":   Scale: %g", dd->scale);
-      DEBUG(PLUGIN_NAME ":   Shift: %g", dd->shift);
-    }
+    snmp_agent_dump_data(td->columns);
   }
 
-  for (llentry_t *e = llist_head(g_agent->scalars); e != NULL; e = e->next) {
-    data_definition_t *dd = e->value;
-
-    DEBUG(PLUGIN_NAME ": Scalar:");
-    DEBUG(PLUGIN_NAME ":   Name: %s", dd->name);
-    if (dd->plugin)
-      DEBUG(PLUGIN_NAME ":   Plugin: %s", dd->plugin);
-    if (dd->plugin_instance)
-      DEBUG(PLUGIN_NAME ":   PluginInstance: %s", dd->plugin_instance);
-    if (dd->is_instance)
-      DEBUG(PLUGIN_NAME ":   Instance: true");
-    if (dd->type)
-      DEBUG(PLUGIN_NAME ":   Type: %s", dd->type);
-    if (dd->type_instance)
-      DEBUG(PLUGIN_NAME ":   TypeInstance: %s", dd->type_instance);
-    for (size_t i = 0; i < dd->oids_len; i++) {
-      snmp_agent_oid_to_string(oid_str, sizeof(oid_str), &dd->oids[i]);
-      DEBUG(PLUGIN_NAME ":   OID[%" PRIsz "]: %s", i, oid_str);
-    }
-    DEBUG(PLUGIN_NAME ":   Scale: %g", dd->scale);
-    DEBUG(PLUGIN_NAME ":   Shift: %g", dd->shift);
-  }
-#endif /* COLLECT_DEBUG */
+  /* Printing scalars */
+  snmp_agent_dump_data(g_agent->scalars);
 }
+#endif /* COLLECT_DEBUG */
 
-static int snmp_agent_validate_data(void) {
+static int snmp_agent_validate_config(void) {
 
-  snmp_agent_dump_data();
+#if COLLECT_DEBUG
+  snmp_agent_dump_config();
+#endif
 
   for (llentry_t *te = llist_head(g_agent->tables); te != NULL; te = te->next) {
     table_definition_t *td = te->value;
 
+    if (!td->index_keys_len) {
+      ERROR(PLUGIN_NAME ": Index keys not defined for '%s'", td->name);
+      return -EINVAL;
+    }
+
     for (llentry_t *de = llist_head(td->columns); de != NULL; de = de->next) {
       data_definition_t *dd = de->value;
 
@@ -227,11 +286,10 @@ static int snmp_agent_validate_data(void) {
         return -EINVAL;
       }
 
-      if (dd->is_instance) {
-
+      if (dd->is_index_key) {
         if (dd->type || dd->type_instance) {
           ERROR(PLUGIN_NAME ": Type and TypeInstance are not valid for "
-                            "instance data '%s'.'%s'",
+                            "index data '%s'.'%s'",
                 td->name, dd->name);
           return -EINVAL;
         }
@@ -267,9 +325,8 @@ static int snmp_agent_validate_data(void) {
       return -EINVAL;
     }
 
-    if (dd->is_instance) {
-      ERROR(PLUGIN_NAME
-            ": Instance flag can't be specified for scalar data '%s'",
+    if (dd->is_index_key) {
+      ERROR(PLUGIN_NAME ": Index field can't be specified for scalar data '%s'",
             dd->name);
       return -EINVAL;
     }
@@ -283,109 +340,420 @@ static int snmp_agent_validate_data(void) {
   return 0;
 }
 
-static void snmp_agent_generate_oid2string(oid_t *oid, size_t offset,
-                                           char *key) {
-  size_t key_len = oid->oid[offset];
-  size_t i;
+static int snmp_agent_parse_index_key(const char *input, regex_t *regex_info,
+                                      int gi, regmatch_t *m) {
+  regmatch_t matches[MAX_MATCHES];
+
+  int ret = regexec(regex_info, input, MAX_MATCHES, matches, 0);
+  if (!ret) {
+    if (gi > regex_info->re_nsub) {
+      ERROR(PLUGIN_NAME ": Group index %d not found. Check regex config", gi);
+      return -1;
+    }
+    *m = matches[gi];
+  } else if (ret == REG_NOMATCH) {
+    ERROR(PLUGIN_NAME ": No match found");
+    return -1;
+  } else {
+    char msgbuf[100];
 
-  for (i = 0; i < key_len && offset < oid->oid_len; i++)
-    key[i] = oid->oid[++offset];
+    regerror(ret, regex_info, msgbuf, sizeof(msgbuf));
+    ERROR(PLUGIN_NAME ": Regex match failed: %s", msgbuf);
+    return -1;
+  }
+
+  return 0;
+}
+
+static int snmp_agent_create_token(char const *input, int t_off, int n,
+                                   c_avl_tree_t *tree,
+                                   netsnmp_variable_list *index_key) {
+  assert(tree != NULL);
+
+  token_t *token = malloc(sizeof(*token));
+
+  if (token == NULL)
+    goto error;
+
+  int *offset = malloc(sizeof(*offset));
+
+  if (offset == NULL)
+    goto free_token_error;
+
+  int ret = 0;
+
+  token->key = index_key;
+  token->str = strndup(input + t_off, n);
+
+  if (token->str == NULL)
+    goto free_offset_error;
+
+  *offset = t_off;
+  ret = c_avl_insert(tree, (void *)offset, (void *)token);
+
+  if (ret == 0)
+    return 0;
+
+  sfree(token->str);
+
+free_offset_error:
+  sfree(offset);
+
+free_token_error:
+  sfree(token);
+
+error:
+  ERROR(PLUGIN_NAME ": Could not allocate memory to create token");
+
+  return -1;
+}
+
+static int snmp_agent_delete_token(int t_off, c_avl_tree_t *tree) {
+  token_t *token = NULL;
+  int *offset = NULL;
+
+  int ret = c_avl_remove(tree, &t_off, (void **)&offset, (void **)&token);
+
+  if (ret != 0) {
+    ERROR(PLUGIN_NAME ": Could not delete token");
+    return -1;
+  }
+
+  sfree(token->str);
+  sfree(token);
+  sfree(offset);
+  return 0;
+}
+
+static int snmp_agent_get_token(c_avl_tree_t *tree, int mpos) {
+
+  int *pos;
+  char *token;
+  int prev_pos = 0;
+
+  c_avl_iterator_t *it = c_avl_get_iterator(tree);
+  while (c_avl_iterator_next(it, (void **)&pos, (void **)&token) == 0) {
+    if (*pos >= mpos)
+      break;
+    else
+      prev_pos = *pos;
+  }
+
+  c_avl_iterator_destroy(it);
+  return prev_pos;
+}
+
+static int snmp_agent_tokenize(const char *input, c_avl_tree_t *tokens,
+                               const regmatch_t *m,
+                               netsnmp_variable_list *key) {
+  assert(tokens != NULL);
+
+  int ret = 0;
+  int len = strlen(input);
+
+  /* Creating first token that is going to be split later */
+  if (c_avl_size(tokens) == 0) {
+    ret = snmp_agent_create_token(input, 0, len, tokens, NULL);
+    if (ret != 0)
+      return ret;
+  }
+
+  /* Divide token that contains current match into two */
+  int t_pos = snmp_agent_get_token(tokens, m->rm_so);
+  ret = snmp_agent_delete_token(t_pos, tokens);
+
+  if (ret != 0)
+    return -1;
+
+  ret = snmp_agent_create_token(input, t_pos, m->rm_so - t_pos, tokens, key);
+
+  if (ret != 0)
+    return -1;
+
+  if (len - m->rm_eo > 1) {
+    ret = snmp_agent_create_token(input, m->rm_eo, len - m->rm_eo + 1, tokens,
+                                  NULL);
+    if (ret != 0) {
+      snmp_agent_delete_token(t_pos, tokens);
+      return -1;
+    }
+  }
 
-  key[i] = '\0';
+  return 0;
 }
 
-static int snmp_agent_generate_string2oid(oid_t *oid, const char *key) {
-  size_t key_len = strlen(key);
+static int snmp_agent_fill_index_list(table_definition_t *td,
+                                      value_list_t const *vl) {
+  int ret;
+  int i;
+  netsnmp_variable_list *key = td->index_list_cont;
+  char const *ptr;
+
+  for (i = 0; i < td->index_keys_len; i++) {
+    /* var should never be NULL */
+    assert(key != NULL);
+    ptr = NULL;
+    ret = 0;
+    const index_key_src_t source = td->index_keys[i].source;
+    c_avl_tree_t *const tokens = td->tokens[source];
+    /* Generating list filled with all data necessary to generate an OID */
+    switch (source) {
+    case INDEX_HOST:
+      ptr = vl->host;
+      break;
+    case INDEX_PLUGIN:
+      ptr = vl->plugin;
+      break;
+    case INDEX_PLUGIN_INSTANCE:
+      ptr = vl->plugin_instance;
+      break;
+    case INDEX_TYPE:
+      ptr = vl->type;
+      break;
+    case INDEX_TYPE_INSTANCE:
+      ptr = vl->type_instance;
+      break;
+    default:
+      ERROR(PLUGIN_NAME ": Unknown index key source provided");
+      return -EINVAL;
+    }
+    if (ret != 0)
+      return -EINVAL;
 
-  oid->oid[oid->oid_len++] = key_len;
-  for (size_t i = 0; i < key_len; i++) {
-    oid->oid[oid->oid_len++] = key[i];
-    if (oid->oid_len >= MAX_OID_LEN) {
-      ERROR(PLUGIN_NAME ": Conversion key string %s to OID failed", key);
+    /* Parsing input string if necessary */
+    if (td->index_keys[i].regex) {
+      regmatch_t m = {-1, -1};
+
+      /* Parsing input string */
+      ret = snmp_agent_parse_index_key(ptr, &td->index_keys[i].regex_info,
+                                       td->index_keys[i].group, &m);
+      if (ret != 0) {
+        ERROR(PLUGIN_NAME ": Error executing regex");
+        return ret;
+      }
+
+      /* Tokenizing input string if not done yet */
+      if (td->tokens_done == false)
+        ret = snmp_agent_tokenize(ptr, tokens, &m, key);
+
+      if (ret != 0)
+        return -1;
+
+      if (td->index_keys[i].type == ASN_INTEGER) {
+        int val = strtol(ptr + m.rm_so, NULL, 0);
+
+#ifdef HAVE_NETSNMP_OLD_API
+        ret = snmp_set_var_value(key, (const u_char *)&val, sizeof(val));
+#else
+        ret = snmp_set_var_value(key, &val, sizeof(val));
+#endif
+      } else
+#ifdef HAVE_NETSNMP_OLD_API
+        ret = snmp_set_var_value(key, (const u_char *)(ptr + m.rm_so),
+                                 m.rm_eo - m.rm_so);
+#else
+        ret = snmp_set_var_value(key, ptr + m.rm_so, m.rm_eo - m.rm_so);
+#endif
+    } else
+#ifdef HAVE_NETSNMP_OLD_API
+      ret = snmp_set_var_value(key, (const u_char *)ptr, strlen(ptr));
+#else
+      ret = snmp_set_var_value(key, ptr, strlen(ptr));
+#endif
+    key = key->next_variable;
+  }
+
+  /* Tokens for all source strings are generated */
+  for (i = 0; i < MAX_KEY_SOURCES; i++)
+    td->tokens_done = true;
+
+  return 0;
+}
+
+static int snmp_agent_prep_index_list(table_definition_t const *td,
+                                      netsnmp_variable_list **index_list) {
+  /* Generating list having only the structure (with no values) letting us
+   * know how to parse an OID*/
+  for (int i = 0; i < td->index_keys_len; i++) {
+    switch (td->index_keys[i].source) {
+    case INDEX_HOST:
+    case INDEX_PLUGIN:
+    case INDEX_PLUGIN_INSTANCE:
+    case INDEX_TYPE:
+    case INDEX_TYPE_INSTANCE:
+      snmp_varlist_add_variable(index_list, NULL, 0, td->index_keys[i].type,
+                                NULL, 0);
+      break;
+    default:
+      ERROR(PLUGIN_NAME ": Unknown index key source provided");
       return -EINVAL;
     }
   }
+  return 0;
+}
+
+static int snmp_agent_generate_index(table_definition_t *td,
+                                     value_list_t const *vl, oid_t *index_oid) {
+
+  /* According to given information by index_keys list
+   * index OID is going to be built
+   */
+  int ret = snmp_agent_fill_index_list(td, vl);
+  if (ret != 0)
+    return -EINVAL;
+
+  /* Building only index part OID (without table prefix OID) */
+  ret = build_oid_noalloc(index_oid->oid, sizeof(index_oid->oid),
+                          &index_oid->oid_len, NULL, 0, td->index_list_cont);
+  if (ret != SNMPERR_SUCCESS) {
+    ERROR(PLUGIN_NAME ": Error building index OID");
+    return -EINVAL;
+  }
+
+  return 0;
+}
+
+/* It appends one OID to the end of another */
+static int snmp_agent_append_oid(oid_t *out, const oid_t *in) {
+
+  if (out->oid_len + in->oid_len > MAX_OID_LEN) {
+    ERROR(PLUGIN_NAME ": Cannot create OID. Output length is too long!");
+    return -EINVAL;
+  }
+  memcpy(&out->oid[out->oid_len], in->oid, in->oid_len * sizeof(oid));
+  out->oid_len += in->oid_len;
 
   return 0;
 }
 
-static int snmp_agent_register_oid_string(oid_t *oid, const char *key,
+static int snmp_agent_register_oid_string(const oid_t *oid,
+                                          const oid_t *index_oid,
                                           Netsnmp_Node_Handler *handler) {
   oid_t new_oid;
 
   memcpy(&new_oid, oid, sizeof(*oid));
-  int ret = snmp_agent_generate_string2oid(&new_oid, key);
+  /* Concatenating two string oids */
+  int ret = snmp_agent_append_oid(&new_oid, index_oid);
   if (ret != 0)
     return ret;
 
   return snmp_agent_register_oid(&new_oid, handler);
 }
 
-static int snmp_agent_unregister_oid_string(oid_t *oid, const char *key) {
+static int snmp_agent_unregister_oid(oid_t *oid) {
+  int ret = c_avl_remove(g_agent->registered_oids, (void *)oid, NULL, NULL);
+
+  if (ret != 0)
+    ERROR(PLUGIN_NAME ": Could not delete registration info");
+
+  return unregister_mib(oid->oid, oid->oid_len);
+}
+
+static int snmp_agent_unregister_oid_string(oid_t *oid,
+                                            const oid_t *index_oid) {
   oid_t new_oid;
+  char oid_str[DATA_MAX_NAME_LEN];
 
   memcpy(&new_oid, oid, sizeof(*oid));
-  int ret = snmp_agent_generate_string2oid(&new_oid, key);
+  /* Concatenating two string oids */
+  int ret = snmp_agent_append_oid(&new_oid, index_oid);
   if (ret != 0)
     return ret;
 
-  return unregister_mib(new_oid.oid, new_oid.oid_len);
+  snmp_agent_oid_to_string(oid_str, sizeof(oid_str), &new_oid);
+  DEBUG(PLUGIN_NAME ": Unregistered handler for OID (%s)", oid_str);
+
+  return snmp_agent_unregister_oid(&new_oid);
 }
 
-static int snmp_agent_table_row_remove(table_definition_t *td,
-                                       const char *instance) {
+static void snmp_agent_table_data_remove(data_definition_t *dd,
+                                         table_definition_t *td,
+                                         oid_t *index_oid) {
   int *index = NULL;
-  char *ins = NULL;
+  oid_t *ind_oid = NULL;
 
   if (td->index_oid.oid_len) {
-    if ((c_avl_get(td->instance_index, instance, (void **)&index) != 0) ||
-        (c_avl_get(td->index_instance, index, (void **)&ins) != 0))
-      return 0;
+    if ((c_avl_get(td->instance_index, index_oid, (void **)&index) != 0) ||
+        (c_avl_get(td->index_instance, index, NULL) != 0))
+      return;
   } else {
-    if (c_avl_get(td->instance_index, instance, (void **)&ins) != 0)
-      return 0;
+    if (c_avl_get(td->instance_index, index_oid, NULL) != 0)
+      return;
   }
 
   pthread_mutex_lock(&g_agent->agentx_lock);
 
-  if (td->index_oid.oid_len)
-    snmp_agent_unregister_oid_index(&td->index_oid, *index);
+  int reg_oids = -1; /* Number of registered oids for given instance */
 
+  for (size_t i = 0; i < dd->oids_len; i++) {
+    if (td->index_oid.oid_len)
+      snmp_agent_unregister_oid_index(&dd->oids[i], *index);
+    else
+      snmp_agent_unregister_oid_string(&dd->oids[i], index_oid);
+
+    reg_oids =
+        snmp_agent_update_instance_oids(td->instance_oids, index_oid, -1);
+  }
+
+  /* Checking if any metrics are left registered */
+  if (reg_oids != 0) {
+    pthread_mutex_unlock(&g_agent->agentx_lock);
+    return;
+  }
+
+  /* All metrics have been unregistered. Unregistering index key OIDs */
+  int keys_processed = 0;
   for (llentry_t *de = llist_head(td->columns); de != NULL; de = de->next) {
-    data_definition_t *dd = de->value;
+    data_definition_t *idd = de->value;
+
+    if (!idd->is_index_key)
+      continue;
 
-    for (size_t i = 0; i < dd->oids_len; i++)
+    for (size_t i = 0; i < idd->oids_len; i++)
       if (td->index_oid.oid_len)
-        snmp_agent_unregister_oid_index(&dd->oids[i], *index);
+        snmp_agent_unregister_oid_index(&idd->oids[i], *index);
       else
-        snmp_agent_unregister_oid_string(&dd->oids[i], ins);
-  }
+        snmp_agent_unregister_oid_string(&idd->oids[i], index_oid);
 
+    if (++keys_processed >= td->index_keys_len)
+      break;
+  }
   pthread_mutex_unlock(&g_agent->agentx_lock);
 
-  DEBUG(PLUGIN_NAME ": Removed row for '%s' table [%d, %s]", td->name,
-        (index != NULL) ? *index : -1, ins);
+  /* All OIDs have been unregistered so we dont need this instance registered
+   * as well */
+  char index_str[DATA_MAX_NAME_LEN];
+
+  if (index == NULL)
+    snmp_agent_oid_to_string(index_str, sizeof(index_str), index_oid);
+  else
+    snprintf(index_str, sizeof(index_str), "%d", *index);
 
   notification_t n = {
       .severity = NOTIF_WARNING, .time = cdtime(), .plugin = PLUGIN_NAME};
   sstrncpy(n.host, hostname_g, sizeof(n.host));
-  sstrncpy(n.plugin_instance, ins, sizeof(n.plugin_instance));
   snprintf(n.message, sizeof(n.message),
-           "Removed data row from table %s instance %s index %d", td->name, ins,
-           (index != NULL) ? *index : -1);
+           "Removed data row from table %s with index %s", td->name, index_str);
+  DEBUG(PLUGIN_NAME ": %s", n.message);
   plugin_dispatch_notification(&n);
 
-  if (td->index_oid.oid_len) {
-    c_avl_remove(td->index_instance, index, NULL, (void **)&ins);
-    c_avl_remove(td->instance_index, instance, NULL, (void **)&index);
+  int *val = NULL;
+
+  c_avl_remove(td->instance_oids, index_oid, NULL, (void **)&val);
+  sfree(val);
+
+  if (index != NULL) {
+    pthread_mutex_lock(&g_agent->agentx_lock);
+    snmp_agent_unregister_oid_index(&td->index_oid, *index);
+    pthread_mutex_unlock(&g_agent->agentx_lock);
+
+    c_avl_remove(td->index_instance, index, NULL, (void **)&ind_oid);
+    c_avl_remove(td->instance_index, index_oid, NULL, (void **)&index);
     sfree(index);
-    sfree(ins);
+    sfree(ind_oid);
   } else {
-    c_avl_remove(td->instance_index, instance, NULL, (void **)&ins);
-    sfree(ins);
+    c_avl_remove(td->instance_index, index_oid, NULL, NULL);
   }
-
-  return 0;
 }
 
 static int snmp_agent_clear_missing(const value_list_t *vl,
@@ -399,11 +767,23 @@ static int snmp_agent_clear_missing(const value_list_t *vl,
     for (llentry_t *de = llist_head(td->columns); de != NULL; de = de->next) {
       data_definition_t *dd = de->value;
 
-      if (!dd->is_instance) {
+      if (!dd->is_index_key) {
         if (CHECK_DD_TYPE(dd, vl->plugin, vl->plugin_instance, vl->type,
                           vl->type_instance)) {
-          snmp_agent_table_row_remove(td, vl->plugin_instance);
-          return 0;
+          oid_t *index_oid = calloc(1, sizeof(*index_oid));
+
+          if (index_oid == NULL) {
+            ERROR(PLUGIN_NAME ": Could not allocate memory for index_oid");
+            return -ENOMEM;
+          }
+
+          int ret = snmp_agent_generate_index(td, vl, index_oid);
+
+          if (ret == 0)
+            snmp_agent_table_data_remove(dd, td, index_oid);
+          sfree(index_oid);
+
+          return ret;
         }
       }
     }
@@ -444,23 +824,22 @@ static void snmp_agent_free_table_columns(table_definition_t *td) {
 
     if (td->index_oid.oid_len) {
       int *index;
-      char *instance;
+      oid_t *index_oid;
 
       c_avl_iterator_t *iter = c_avl_get_iterator(td->index_instance);
-      while (c_avl_iterator_next(iter, (void *)&index, (void *)&instance) ==
+      while (c_avl_iterator_next(iter, (void *)&index, (void *)&index_oid) ==
              0) {
         for (size_t i = 0; i < dd->oids_len; i++)
           snmp_agent_unregister_oid_index(&dd->oids[i], *index);
       }
       c_avl_iterator_destroy(iter);
     } else {
-      char *instance;
+      oid_t *index_oid;
 
       c_avl_iterator_t *iter = c_avl_get_iterator(dd->table->instance_index);
-      while (c_avl_iterator_next(iter, (void *)&instance, (void *)&instance) ==
-             0) {
+      while (c_avl_iterator_next(iter, (void *)&index_oid, NULL) == 0) {
         for (size_t i = 0; i < dd->oids_len; i++)
-          snmp_agent_unregister_oid_string(&dd->oids[i], instance);
+          snmp_agent_unregister_oid_string(&dd->oids[i], index_oid);
       }
       c_avl_iterator_destroy(iter);
     }
@@ -480,13 +859,14 @@ static void snmp_agent_free_table(table_definition_t **td) {
   if ((*td)->size_oid.oid_len)
     unregister_mib((*td)->size_oid.oid, (*td)->size_oid.oid_len);
 
+  oid_t *index_oid;
+
   /* Unregister Index OIDs */
   if ((*td)->index_oid.oid_len) {
     int *index;
-    char *instance;
 
     c_avl_iterator_t *iter = c_avl_get_iterator((*td)->index_instance);
-    while (c_avl_iterator_next(iter, (void *)&index, (void *)&instance) == 0)
+    while (c_avl_iterator_next(iter, (void **)&index, (void **)&index_oid) == 0)
       snmp_agent_unregister_oid_index(&(*td)->index_oid, *index);
 
     c_avl_iterator_destroy(iter);
@@ -497,6 +877,15 @@ static void snmp_agent_free_table(table_definition_t **td) {
 
   void *key = NULL;
   void *value = NULL;
+  int *num = NULL;
+
+  /* Removing data from instance_oids, leaving key pointers since they are still
+   * used in other AVL trees */
+  c_avl_iterator_t *iter = c_avl_get_iterator((*td)->instance_oids);
+  while (c_avl_iterator_next(iter, (void **)&index_oid, (void **)&num) == 0)
+    sfree(num);
+  c_avl_iterator_destroy(iter);
+  c_avl_destroy((*td)->instance_oids);
 
   /* index_instance and instance_index contain the same pointers */
   c_avl_destroy((*td)->index_instance);
@@ -511,20 +900,189 @@ static void snmp_agent_free_table(table_definition_t **td) {
     c_avl_destroy((*td)->instance_index);
     (*td)->instance_index = NULL;
   }
+  snmp_free_varbind((*td)->index_list_cont);
 
+  int i;
+  token_t *tok = NULL;
+
+  for (i = 0; i < (*td)->index_keys_len; i++) {
+    sfree((*td)->index_keys[i].regex);
+    regfree(&(*td)->index_keys[i].regex_info);
+  }
+  for (i = 0; i < MAX_KEY_SOURCES; i++)
+    if ((*td)->tokens[i] != NULL) {
+      while (c_avl_pick((*td)->tokens[i], &key, (void **)&tok) == 0) {
+        sfree(key);
+        sfree(tok->str);
+        sfree(tok);
+      }
+      c_avl_destroy((*td)->tokens[i]);
+      (*td)->tokens[i] = NULL;
+    }
   sfree((*td)->name);
   sfree(*td);
 
   return;
 }
 
+static int snmp_agent_parse_oid_index_keys(const table_definition_t *td,
+                                           oid_t *index_oid) {
+  int ret = parse_oid_indexes(index_oid->oid, index_oid->oid_len,
+                              td->index_list_cont);
+  if (ret != SNMPERR_SUCCESS)
+    ERROR(PLUGIN_NAME ": index OID parse error!");
+  return ret;
+}
+
+static int snmp_agent_build_name(char **name, c_avl_tree_t *tokens) {
+
+  int *pos;
+  token_t *tok;
+  char str[DATA_MAX_NAME_LEN];
+  char out[DATA_MAX_NAME_LEN] = {0};
+  c_avl_iterator_t *it = c_avl_get_iterator(tokens);
+
+  if (it == NULL) {
+    ERROR(PLUGIN_NAME ": Error getting tokens list iterator");
+    return -1;
+  }
+
+  while (c_avl_iterator_next(it, (void **)&pos, (void **)&tok) == 0) {
+    strncat(out, tok->str, strlen(tok->str));
+    if (tok->key != NULL) {
+      if (tok->key->type == ASN_INTEGER) {
+        snprintf(str, sizeof(str), "%ld", *tok->key->val.integer);
+        strncat(out, str, strlen(str));
+      } else { /* OCTET_STR */
+        strncat(out, (char *)tok->key->val.string,
+                strlen((char *)tok->key->val.string));
+      }
+    }
+  }
+  *name = strdup(out);
+  c_avl_iterator_destroy(it);
+
+  if (*name == NULL) {
+    ERROR(PLUGIN_NAME ": Could not allocate memory");
+    return -ENOMEM;
+  }
+
+  return 0;
+}
+
+static int snmp_agent_format_name(char *name, int name_len,
+                                  data_definition_t *dd, oid_t *index_oid) {
+
+  int ret = 0;
+
+  if (index_oid == NULL) {
+    /* It's a scalar */
+    format_name(name, name_len, hostname_g, dd->plugin, dd->plugin_instance,
+                dd->type, dd->type_instance);
+  } else {
+    /* Need to parse string index OID */
+    const table_definition_t *td = dd->table;
+    ret = snmp_agent_parse_oid_index_keys(td, index_oid);
+    if (ret != 0)
+      return ret;
+
+    int i = 0;
+    netsnmp_variable_list *key = td->index_list_cont;
+    char str[DATA_MAX_NAME_LEN];
+    char *fields[MAX_KEY_SOURCES] = {hostname_g, dd->plugin,
+                                     dd->plugin_instance, dd->type,
+                                     dd->type_instance};
+
+    /* Looking for simple keys only */
+    while (key != NULL) {
+      if (!td->index_keys[i].regex) {
+        index_key_src_t source = td->index_keys[i].source;
+
+        if (source < INDEX_HOST || source > INDEX_TYPE_INSTANCE) {
+          ERROR(PLUGIN_NAME ": Unkown index key source!");
+          return -EINVAL;
+        }
+
+        if (td->index_keys[i].type == ASN_INTEGER) {
+          snprintf(str, sizeof(str), "%ld", *key->val.integer);
+          fields[source] = str;
+        } else /* OCTET_STR */
+          fields[source] = (char *)key->val.string;
+      }
+      key = key->next_variable;
+      i++;
+    }
+
+    /* Keys with regexes */
+    for (i = 0; i < MAX_KEY_SOURCES; i++) {
+      if (td->tokens[i] == NULL)
+        continue;
+      ret = snmp_agent_build_name(&fields[i], td->tokens[i]);
+      if (ret != 0)
+        return ret;
+    }
+    format_name(name, name_len, fields[INDEX_HOST], fields[INDEX_PLUGIN],
+                fields[INDEX_PLUGIN_INSTANCE], fields[INDEX_TYPE],
+                fields[INDEX_TYPE_INSTANCE]);
+    for (i = 0; i < MAX_KEY_SOURCES; i++) {
+      if (td->tokens[i])
+        sfree(fields[i]);
+    }
+  }
+
+  return 0;
+}
+
 static int snmp_agent_form_reply(struct netsnmp_request_info_s *requests,
-                                 data_definition_t *dd, char *instance,
+                                 data_definition_t *dd, oid_t *index_oid,
                                  int oid_index) {
+  int ret;
+
+  if (dd->is_index_key) {
+    const table_definition_t *td = dd->table;
+    int ret = snmp_agent_parse_oid_index_keys(td, index_oid);
+
+    if (ret != 0)
+      return ret;
+
+    netsnmp_variable_list *key = td->index_list_cont;
+    /* Searching index key */
+    for (int pos = 0; pos < dd->index_key_pos; pos++)
+      key = key->next_variable;
+
+    requests->requestvb->type = td->index_keys[dd->index_key_pos].type;
+
+    if (requests->requestvb->type == ASN_INTEGER)
+#ifdef HAVE_NETSNMP_OLD_API
+      snmp_set_var_typed_value(requests->requestvb, requests->requestvb->type,
+                               (const u_char *)key->val.integer,
+                               sizeof(*key->val.integer));
+#else
+      snmp_set_var_typed_value(requests->requestvb, requests->requestvb->type,
+                               key->val.integer, sizeof(*key->val.integer));
+#endif
+    else /* OCTET_STR */
+#ifdef HAVE_NETSNMP_OLD_API
+      snmp_set_var_typed_value(requests->requestvb, requests->requestvb->type,
+                               (const u_char *)key->val.string,
+                               strlen((const char *)key->val.string));
+#else
+      snmp_set_var_typed_value(requests->requestvb, requests->requestvb->type,
+                               key->val.string,
+                               strlen((const char *)key->val.string));
+#endif
+
+    pthread_mutex_unlock(&g_agent->lock);
+
+    return SNMP_ERR_NOERROR;
+  }
+
   char name[DATA_MAX_NAME_LEN];
-  format_name(name, sizeof(name), hostname_g, dd->plugin,
-              instance ? instance : dd->plugin_instance, dd->type,
-              dd->type_instance);
+
+  ret = snmp_agent_format_name(name, sizeof(name), dd, index_oid);
+  if (ret != 0)
+    return ret;
+
   DEBUG(PLUGIN_NAME ": Identifier '%s'", name);
 
   value_t *values;
@@ -535,7 +1093,7 @@ static int snmp_agent_form_reply(struct netsnmp_request_info_s *requests,
     return SNMP_NOSUCHINSTANCE;
   }
 
-  int ret = uc_get_value_by_name(name, &values, &values_num);
+  ret = uc_get_value_by_name(name, &values, &values_num);
 
   if (ret != 0) {
     ERROR(PLUGIN_NAME ": Failed to get value for '%s'", name);
@@ -571,14 +1129,14 @@ snmp_agent_table_oid_handler(struct netsnmp_mib_handler_s *handler,
                              struct netsnmp_agent_request_info_s *reqinfo,
                              struct netsnmp_request_info_s *requests) {
 
-  if (reqinfo->mode != MODE_GET && reqinfo->mode != MODE_GETNEXT) {
+  if (reqinfo->mode != MODE_GET) {
     DEBUG(PLUGIN_NAME ": Not supported request mode (%d)", reqinfo->mode);
     return SNMP_ERR_NOERROR;
   }
 
   pthread_mutex_lock(&g_agent->lock);
 
-  oid_t oid;
+  oid_t oid; /* Requested OID */
   memcpy(oid.oid, requests->requestvb->name,
          sizeof(oid.oid[0]) * requests->requestvb->name_length);
   oid.oid_len = requests->requestvb->name_length;
@@ -588,6 +1146,7 @@ snmp_agent_table_oid_handler(struct netsnmp_mib_handler_s *handler,
   snmp_agent_oid_to_string(oid_str, sizeof(oid_str), &oid);
   DEBUG(PLUGIN_NAME ": Get request received for table OID '%s'", oid_str);
 #endif
+  oid_t index_oid; /* Index part of requested OID */
 
   for (llentry_t *te = llist_head(g_agent->tables); te != NULL; te = te->next) {
     table_definition_t *td = te->value;
@@ -598,49 +1157,37 @@ snmp_agent_table_oid_handler(struct netsnmp_mib_handler_s *handler,
       for (size_t i = 0; i < dd->oids_len; i++) {
         int ret = snmp_oid_ncompare(oid.oid, oid.oid_len, dd->oids[i].oid,
                                     dd->oids[i].oid_len,
-                                    MIN(oid.oid_len, dd->oids[i].oid_len));
+                                    SNMP_MIN(oid.oid_len, dd->oids[i].oid_len));
         if (ret != 0)
           continue;
 
-        char *instance;
-
-        if (!td->index_oid.oid_len) {
-          char key[MAX_OID_LEN];
+        /* Calculating OID length for index part */
+        index_oid.oid_len = oid.oid_len - dd->oids[i].oid_len;
+        /* Fetching index part of the OID */
+        memcpy(index_oid.oid, &oid.oid[dd->oids[i].oid_len],
+               index_oid.oid_len * sizeof(*oid.oid));
 
-          memset(key, 0, sizeof(key));
-          snmp_agent_generate_oid2string(
-              &oid, MIN(oid.oid_len, dd->oids[i].oid_len), key);
+        char index_str[DATA_MAX_NAME_LEN];
+        snmp_agent_oid_to_string(index_str, sizeof(index_str), &index_oid);
 
-          ret = c_avl_get(td->instance_index, key, (void **)&instance);
-          if (ret != 0) {
-            DEBUG(PLUGIN_NAME ": Nonexisting index string '%s' requested", key);
-            pthread_mutex_unlock(&g_agent->lock);
-            return SNMP_NOSUCHINSTANCE;
-          }
+        if (!td->index_oid.oid_len) {
+          ret = c_avl_get(td->instance_index, &index_oid, NULL);
         } else {
-          int index = oid.oid[oid.oid_len - 1];
+          oid_t *temp_oid;
 
-          ret = c_avl_get(td->index_instance, &index, (void **)&instance);
-          if (ret != 0) {
-            DEBUG(PLUGIN_NAME ": Nonexisting index '%d' requested", index);
-            pthread_mutex_unlock(&g_agent->lock);
-            return SNMP_NOSUCHINSTANCE;
-          }
+          assert(index_oid.oid_len == 1);
+          ret = c_avl_get(td->index_instance, (int *)&index_oid.oid[0],
+                          (void **)&temp_oid);
+          memcpy(&index_oid, temp_oid, sizeof(index_oid));
         }
 
-        if (dd->is_instance) {
-          requests->requestvb->type = ASN_OCTET_STR;
-          snmp_set_var_typed_value(
-              requests->requestvb, requests->requestvb->type,
-              (const u_char *)instance, strlen((instance)));
-
+        if (ret != 0) {
+          INFO(PLUGIN_NAME ": Non-existing index (%s) requested", index_str);
           pthread_mutex_unlock(&g_agent->lock);
-
-          return SNMP_ERR_NOERROR;
+          return SNMP_NOSUCHINSTANCE;
         }
 
-        ret = snmp_agent_form_reply(requests, dd, instance, i);
-
+        ret = snmp_agent_form_reply(requests, dd, &index_oid, i);
         pthread_mutex_unlock(&g_agent->lock);
 
         return ret;
@@ -659,7 +1206,7 @@ static int snmp_agent_table_index_oid_handler(
     struct netsnmp_agent_request_info_s *reqinfo,
     struct netsnmp_request_info_s *requests) {
 
-  if (reqinfo->mode != MODE_GET && reqinfo->mode != MODE_GETNEXT) {
+  if (reqinfo->mode != MODE_GET) {
     DEBUG(PLUGIN_NAME ": Not supported request mode (%d)", reqinfo->mode);
     return SNMP_ERR_NOERROR;
   }
@@ -675,15 +1222,15 @@ static int snmp_agent_table_index_oid_handler(
     table_definition_t *td = te->value;
 
     if (td->index_oid.oid_len &&
-        (snmp_oid_ncompare(oid.oid, oid.oid_len, td->index_oid.oid,
-                           td->index_oid.oid_len,
-                           MIN(oid.oid_len, td->index_oid.oid_len)) == 0)) {
+        (snmp_oid_ncompare(
+             oid.oid, oid.oid_len, td->index_oid.oid, td->index_oid.oid_len,
+             SNMP_MIN(oid.oid_len, td->index_oid.oid_len)) == 0)) {
 
       DEBUG(PLUGIN_NAME ": Handle '%s' table index OID", td->name);
 
       int index = oid.oid[oid.oid_len - 1];
 
-      int ret = c_avl_get(td->index_instance, &index, &(void *){NULL});
+      int ret = c_avl_get(td->index_instance, &index, NULL);
       if (ret != 0) {
         /* nonexisting index requested */
         pthread_mutex_unlock(&g_agent->lock);
@@ -711,7 +1258,7 @@ static int snmp_agent_table_size_oid_handler(
     struct netsnmp_agent_request_info_s *reqinfo,
     struct netsnmp_request_info_s *requests) {
 
-  if (reqinfo->mode != MODE_GET && reqinfo->mode != MODE_GETNEXT) {
+  if (reqinfo->mode != MODE_GET) {
     DEBUG(PLUGIN_NAME ": Not supported request mode (%d)", reqinfo->mode);
     return SNMP_ERR_NOERROR;
   }
@@ -731,12 +1278,16 @@ static int snmp_agent_table_size_oid_handler(
     if (td->size_oid.oid_len &&
         (snmp_oid_ncompare(oid.oid, oid.oid_len, td->size_oid.oid,
                            td->size_oid.oid_len,
-                           MIN(oid.oid_len, td->size_oid.oid_len)) == 0)) {
+                           SNMP_MIN(oid.oid_len, td->size_oid.oid_len)) == 0)) {
       DEBUG(PLUGIN_NAME ": Handle '%s' table size OID", td->name);
 
-      long size = c_avl_size(td->index_instance);
+      long size;
+      if (td->index_oid.oid_len)
+        size = c_avl_size(td->index_instance);
+      else
+        size = c_avl_size(td->instance_index);
 
-      requests->requestvb->type = td->size_oid.type;
+      requests->requestvb->type = ASN_INTEGER;
       snmp_set_var_typed_value(requests->requestvb, requests->requestvb->type,
                                (const u_char *)&size, sizeof(size));
 
@@ -757,7 +1308,7 @@ snmp_agent_scalar_oid_handler(struct netsnmp_mib_handler_s *handler,
                               struct netsnmp_agent_request_info_s *reqinfo,
                               struct netsnmp_request_info_s *requests) {
 
-  if (reqinfo->mode != MODE_GET && reqinfo->mode != MODE_GETNEXT) {
+  if (reqinfo->mode != MODE_GET) {
     DEBUG(PLUGIN_NAME ": Not supported request mode (%d)", reqinfo->mode);
     return SNMP_ERR_NOERROR;
   }
@@ -860,10 +1411,14 @@ static int snmp_agent_config_data_oids(data_definition_t *dd,
       return -EINVAL;
     }
 
-  if (dd->oids != NULL)
-    sfree(dd->oids);
+  if (dd->oids != NULL) {
+    WARNING(PLUGIN_NAME ": OIDs can be configured only once for each data");
+    return -EINVAL;
+  }
+
   dd->oids_len = 0;
   dd->oids = calloc(ci->values_num, sizeof(*dd->oids));
+
   if (dd->oids == NULL)
     return -ENOMEM;
   dd->oids_len = (size_t)ci->values_num;
@@ -935,98 +1490,125 @@ static int snmp_agent_config_table_index_oid(table_definition_t *td,
   return 0;
 }
 
-static int snmp_agent_config_table_data(table_definition_t *td,
-                                        oconfig_item_t *ci) {
-  data_definition_t *dd;
-  int ret = 0;
+/* Getting index key source that will represent table row */
+static int snmp_agent_config_index_key_source(table_definition_t *td,
+                                              data_definition_t *dd,
+                                              oconfig_item_t *ci) {
+  char *val = NULL;
 
-  assert(ci != NULL);
+  int ret = cf_util_get_string(ci, &val);
+  if (ret != 0)
+    return -1;
 
-  dd = calloc(1, sizeof(*dd));
-  if (dd == NULL) {
-    ERROR(PLUGIN_NAME ": Failed to allocate memory for table data definition");
-    return -ENOMEM;
+  bool match = false;
+
+  for (int i = 0; i < MAX_KEY_SOURCES; i++) {
+    if (strcasecmp(index_opts[i], (const char *)val) == 0) {
+      td->index_keys[td->index_keys_len].source = i;
+      td->index_keys[td->index_keys_len].group = GROUP_UNUSED;
+      td->index_keys[td->index_keys_len].regex = NULL;
+      match = 1;
+      break;
+    }
   }
 
-  ret = cf_util_get_string(ci, &dd->name);
-  if (ret != 0) {
-    sfree(dd);
-    return -1;
+  if (!match) {
+    ERROR(PLUGIN_NAME ": Failed to parse index key source: '%s'", val);
+    sfree(val);
+    return -EINVAL;
   }
 
-  dd->scale = 1.0;
-  dd->shift = 0.0;
+  sfree(val);
+  dd->index_key_pos = td->index_keys_len++;
+  dd->is_index_key = true;
 
-  dd->table = td;
+  return 0;
+}
 
-  for (int i = 0; i < ci->children_num; i++) {
-    oconfig_item_t *option = ci->children + i;
+/* Getting format string used to parse values from index key source */
+static int snmp_agent_config_index_key_regex(table_definition_t *td,
+                                             data_definition_t *dd,
+                                             oconfig_item_t *ci) {
+  index_key_t *index_key = &td->index_keys[dd->index_key_pos];
 
-    if (strcasecmp("Instance", option->key) == 0)
-      ret = cf_util_get_boolean(option, &dd->is_instance);
-    else if (strcasecmp("Plugin", option->key) == 0)
-      ret = cf_util_get_string(option, &dd->plugin);
-    else if (strcasecmp("PluginInstance", option->key) == 0)
-      ret = cf_util_get_string(option, &dd->plugin_instance);
-    else if (strcasecmp("Type", option->key) == 0)
-      ret = cf_util_get_string(option, &dd->type);
-    else if (strcasecmp("TypeInstance", option->key) == 0)
-      ret = cf_util_get_string(option, &dd->type_instance);
-    else if (strcasecmp("Shift", option->key) == 0)
-      ret = cf_util_get_double(option, &dd->shift);
-    else if (strcasecmp("Scale", option->key) == 0)
-      ret = cf_util_get_double(option, &dd->scale);
-    else if (strcasecmp("OIDs", option->key) == 0)
-      ret = snmp_agent_config_data_oids(dd, option);
-    else {
-      WARNING(PLUGIN_NAME ": Option `%s' not allowed here", option->key);
-      ret = -1;
-    }
+  int ret = cf_util_get_string(ci, &index_key->regex);
+  if (ret != 0)
+    return -1;
 
-    if (ret != 0) {
-      snmp_agent_free_data(&dd);
-      return -1;
-    }
+  ret = regcomp(&index_key->regex_info, index_key->regex, REG_EXTENDED);
+  if (ret) {
+    ERROR(PLUGIN_NAME ": Could not compile regex for %s", dd->name);
+    return -1;
   }
 
-  llentry_t *entry = llentry_create(dd->name, dd);
-  if (entry == NULL) {
-    snmp_agent_free_data(&dd);
-    return -ENOMEM;
+  index_key_src_t source = index_key->source;
+  if (td->tokens[source] == NULL) {
+    td->tokens[source] =
+        c_avl_create((int (*)(const void *, const void *))num_compare);
+    if (td->tokens[source] == NULL) {
+      ERROR(PLUGIN_NAME ": Could not allocate memory for AVL tree");
+      return -ENOMEM;
+    }
   }
 
-  llist_append(td->columns, entry);
-
   return 0;
 }
 
-static int snmp_agent_config_data(oconfig_item_t *ci) {
+static int snmp_agent_config_index_key(table_definition_t *td,
+                                       data_definition_t *dd,
+                                       oconfig_item_t *ci) {
+  int ret = 0;
+
+  for (int i = 0; (i < ci->children_num && ret == 0); i++) {
+    oconfig_item_t *option = ci->children + i;
+
+    if (strcasecmp("Source", option->key) == 0)
+      ret = snmp_agent_config_index_key_source(td, dd, option);
+    else if (strcasecmp("Regex", option->key) == 0)
+      ret = snmp_agent_config_index_key_regex(td, dd, option);
+    else if (strcasecmp("Group", option->key) == 0)
+      ret = cf_util_get_int(option, &td->index_keys[dd->index_key_pos].group);
+  }
+
+  return ret;
+}
+
+/* This function parses configuration of both scalar and table column
+ * because they have nearly the same structure */
+static int snmp_agent_config_table_column(table_definition_t *td,
+                                          oconfig_item_t *ci) {
   data_definition_t *dd;
   int ret = 0;
+  oconfig_item_t *option_tmp = NULL;
 
   assert(ci != NULL);
 
   dd = calloc(1, sizeof(*dd));
   if (dd == NULL) {
-    ERROR(PLUGIN_NAME ": Failed to allocate memory for data definition");
+    ERROR(PLUGIN_NAME ": Failed to allocate memory for table data definition");
     return -ENOMEM;
   }
 
   ret = cf_util_get_string(ci, &dd->name);
   if (ret != 0) {
-    free(dd);
+    sfree(dd);
     return -1;
   }
 
   dd->scale = 1.0;
   dd->shift = 0.0;
+  /* NULL if it's a scalar */
+  dd->table = td;
+  dd->is_index_key = false;
 
   for (int i = 0; i < ci->children_num; i++) {
     oconfig_item_t *option = ci->children + i;
 
-    if (strcasecmp("Instance", option->key) == 0)
-      ret = cf_util_get_boolean(option, &dd->is_instance);
-    else if (strcasecmp("Plugin", option->key) == 0)
+    /* First 3 options are reserved for table entry only */
+    if (td != NULL && strcasecmp("IndexKey", option->key) == 0) {
+      dd->is_index_key = true;
+      option_tmp = option;
+    } else if (strcasecmp("Plugin", option->key) == 0)
       ret = cf_util_get_string(option, &dd->plugin);
     else if (strcasecmp("PluginInstance", option->key) == 0)
       ret = cf_util_get_string(option, &dd->plugin_instance);
@@ -1051,17 +1633,37 @@ static int snmp_agent_config_data(oconfig_item_t *ci) {
     }
   }
 
+  if (dd->is_index_key) {
+    ret = snmp_agent_config_index_key(td, dd, option_tmp);
+    td->index_keys[dd->index_key_pos].type =
+        snmp_agent_get_asn_type(dd->oids[0].oid, dd->oids[0].oid_len);
+
+    if (ret != 0) {
+      snmp_agent_free_data(&dd);
+      return -1;
+    }
+  }
+
   llentry_t *entry = llentry_create(dd->name, dd);
   if (entry == NULL) {
     snmp_agent_free_data(&dd);
     return -ENOMEM;
   }
 
-  llist_append(g_agent->scalars, entry);
+  /* Append to column list in parent table */
+  if (td != NULL)
+    llist_append(td->columns, entry);
+  else
+    llentry_destroy(entry);
 
   return 0;
 }
 
+/* Parses scalar configuration entry */
+static int snmp_agent_config_scalar(oconfig_item_t *ci) {
+  return snmp_agent_config_table_column(NULL, ci);
+}
+
 static int num_compare(const int *a, const int *b) {
   assert((a != NULL) && (b != NULL));
   if (*a < *b)
@@ -1072,6 +1674,10 @@ static int num_compare(const int *a, const int *b) {
     return 0;
 }
 
+static int oid_compare(const oid_t *a, const oid_t *b) {
+  return snmp_oid_compare(a->oid, a->oid_len, b->oid, b->oid_len);
+}
+
 static int snmp_agent_config_table(oconfig_item_t *ci) {
   table_definition_t *td;
   int ret = 0;
@@ -1097,6 +1703,10 @@ static int snmp_agent_config_table(oconfig_item_t *ci) {
     return -ENOMEM;
   }
 
+  for (int i = 0; i < MAX_KEY_SOURCES; i++)
+    td->tokens[i] = NULL;
+  td->tokens_done = false;
+
   for (int i = 0; i < ci->children_num; i++) {
     oconfig_item_t *option = ci->children + i;
 
@@ -1105,7 +1715,7 @@ static int snmp_agent_config_table(oconfig_item_t *ci) {
     else if (strcasecmp("SizeOID", option->key) == 0)
       ret = snmp_agent_config_table_size_oid(td, option);
     else if (strcasecmp("Data", option->key) == 0)
-      ret = snmp_agent_config_table_data(td, option);
+      ret = snmp_agent_config_table_column(td, option);
     else {
       WARNING(PLUGIN_NAME ": Option `%s' not allowed here", option->key);
       ret = -1;
@@ -1117,8 +1727,13 @@ static int snmp_agent_config_table(oconfig_item_t *ci) {
     }
   }
 
+  /* Preparing index list container */
+  ret = snmp_agent_prep_index_list(td, &td->index_list_cont);
+  if (ret != 0)
+    return -EINVAL;
+
   td->instance_index =
-      c_avl_create((int (*)(const void *, const void *))strcmp);
+      c_avl_create((int (*)(const void *, const void *))oid_compare);
   if (td->instance_index == NULL) {
     snmp_agent_free_table(&td);
     return -ENOMEM;
@@ -1131,11 +1746,19 @@ static int snmp_agent_config_table(oconfig_item_t *ci) {
     return -ENOMEM;
   }
 
+  td->instance_oids =
+      c_avl_create((int (*)(const void *, const void *))oid_compare);
+  if (td->instance_oids == NULL) {
+    snmp_agent_free_table(&td);
+    return -ENOMEM;
+  }
+
   llentry_t *entry = llentry_create(td->name, td);
   if (entry == NULL) {
     snmp_agent_free_table(&td);
     return -ENOMEM;
   }
+
   llist_append(g_agent->tables, entry);
 
   return 0;
@@ -1236,98 +1859,170 @@ static int snmp_agent_unregister_oid_index(oid_t *oid, int index) {
   oid_t new_oid;
   memcpy(&new_oid, oid, sizeof(*oid));
   new_oid.oid[new_oid.oid_len++] = index;
-  return unregister_mib(new_oid.oid, new_oid.oid_len);
+  return snmp_agent_unregister_oid(&new_oid);
 }
 
-static int snmp_agent_update_index(table_definition_t *td,
-                                   const char *instance) {
+static int snmp_agent_update_instance_oids(c_avl_tree_t *tree, oid_t *index_oid,
+                                           int value) {
+  int *oids_num; /* number of oids registered for instance */
 
-  if (c_avl_get(td->instance_index, instance, NULL) == 0)
-    return 0;
+  if (c_avl_get(tree, index_oid, (void **)&oids_num) == 0) {
+    *oids_num += value;
+    return *oids_num;
+  } else {
+    ERROR(PLUGIN_NAME ": Error updating index data");
+    return -1;
+  }
+}
 
+static int snmp_agent_update_index(data_definition_t *dd,
+                                   table_definition_t *td, oid_t **index_oid) {
   int ret;
   int *index = NULL;
-  char *ins;
+  int *value = NULL;
+  bool do_free_index_oid = true;
 
-  ins = strdup(instance);
-  if (ins == NULL)
-    return -ENOMEM;
+  if (c_avl_get(td->instance_index, (void *)*index_oid, (void **)&index) != 0) {
+    /* Processing new instance */
+    do_free_index_oid = false;
 
-  /* need to generate index for the table */
-  if (td->index_oid.oid_len) {
-    index = calloc(1, sizeof(*index));
-    if (index == NULL) {
-      sfree(ins);
-      return -ENOMEM;
+    /* need to generate index for the table */
+    if (td->index_oid.oid_len) {
+      index = calloc(1, sizeof(*index));
+      if (index == NULL) {
+        ret = -ENOMEM;
+        goto free_index_oid;
+      }
+
+      *index = c_avl_size(td->instance_index) + 1;
+
+      ret = c_avl_insert(td->instance_index, *index_oid, index);
+      if (ret != 0)
+        goto free_index;
+
+      ret = c_avl_insert(td->index_instance, index, *index_oid);
+      if (ret < 0) {
+        DEBUG(PLUGIN_NAME ": Failed to update index_instance for '%s' table",
+              td->name);
+        goto remove_avl_index_oid;
+      }
+
+      ret = snmp_agent_register_oid_index(&td->index_oid, *index,
+                                          snmp_agent_table_index_oid_handler);
+      if (ret != 0)
+        goto remove_avl_index;
+    } else {
+      /* instance as a key is required for any table */
+      ret = c_avl_insert(td->instance_index, *index_oid, NULL);
+      if (ret != 0)
+        goto free_index_oid;
     }
 
-    *index = c_avl_size(td->instance_index) + 1;
+    value = calloc(1, sizeof(*value));
 
-    ret = c_avl_insert(td->instance_index, ins, index);
-    if (ret != 0) {
-      sfree(ins);
-      sfree(index);
-      return ret;
+    if (value == NULL) {
+      ERROR(PLUGIN_NAME ": Failed to allocate memory");
+      ret = -ENOMEM;
+      goto unregister_index;
     }
 
-    ret = c_avl_insert(td->index_instance, index, ins);
+    ret = c_avl_insert(td->instance_oids, *index_oid, value);
+
     if (ret < 0) {
-      DEBUG(PLUGIN_NAME ": Failed to update index_instance for '%s' table",
+      DEBUG(PLUGIN_NAME ": Failed to update instance_oids for '%s' table",
             td->name);
-      c_avl_remove(td->instance_index, ins, NULL, (void **)&index);
-      sfree(ins);
-      sfree(index);
-      return ret;
+      goto free_value;
     }
 
-    ret = snmp_agent_register_oid_index(&td->index_oid, *index,
-                                        snmp_agent_table_index_oid_handler);
-    if (ret != 0)
-      return ret;
-  } else {
-    /* instance as a key is required for any table */
-    ret = c_avl_insert(td->instance_index, ins, ins);
-    if (ret != 0) {
-      sfree(ins);
-      return ret;
-    }
-  }
+    int keys_processed = 0;
 
-  /* register new oids for all columns */
-  for (llentry_t *de = llist_head(td->columns); de != NULL; de = de->next) {
-    data_definition_t *dd = de->value;
+    /* Registering index keys OIDs */
+    for (llentry_t *de = llist_head(td->columns); de != NULL; de = de->next) {
+      data_definition_t *idd = de->value;
+      if (!idd->is_index_key)
+        continue;
 
-    for (size_t i = 0; i < dd->oids_len; i++) {
-      if (td->index_oid.oid_len) {
-        ret = snmp_agent_register_oid_index(&dd->oids[i], *index,
-                                            snmp_agent_table_oid_handler);
-      } else {
-        ret = snmp_agent_register_oid_string(&dd->oids[i], ins,
-                                             snmp_agent_table_oid_handler);
+      for (size_t i = 0; i < idd->oids_len; i++) {
+        if (td->index_oid.oid_len)
+          ret = snmp_agent_register_oid_index(&idd->oids[i], *index,
+                                              snmp_agent_table_oid_handler);
+        else
+          ret = snmp_agent_register_oid_string(&idd->oids[i], *index_oid,
+                                               snmp_agent_table_oid_handler);
+
+        if (ret != 0) {
+          ERROR(PLUGIN_NAME ": Could not register OID");
+          goto free_index;
+        }
       }
 
-      if (ret != 0)
-        return ret;
+      if (++keys_processed >= td->index_keys_len)
+        break;
     }
   }
 
-  DEBUG(PLUGIN_NAME ": Updated index for '%s' table [%d, %s]", td->name,
-        (index != NULL) ? *index : -1, ins);
+  ret = 0;
 
-  notification_t n = {
-      .severity = NOTIF_OKAY, .time = cdtime(), .plugin = PLUGIN_NAME};
-  sstrncpy(n.host, hostname_g, sizeof(n.host));
-  sstrncpy(n.plugin_instance, ins, sizeof(n.plugin_instance));
-  snprintf(n.message, sizeof(n.message),
-           "Data row added to table %s instance %s index %d", td->name, ins,
-           (index != NULL) ? *index : -1);
-  plugin_dispatch_notification(&n);
+  for (size_t i = 0; i < dd->oids_len; i++) {
+    if (td->index_oid.oid_len)
+      ret = snmp_agent_register_oid_index(&dd->oids[i], *index,
+                                          snmp_agent_table_oid_handler);
+    else
+      ret = snmp_agent_register_oid_string(&dd->oids[i], *index_oid,
+                                           snmp_agent_table_oid_handler);
+
+    if (ret < 0)
+      goto free_index;
+    else if (ret == OID_EXISTS)
+      break;
+    else if (snmp_agent_update_instance_oids(td->instance_oids, *index_oid, 1) <
+             0)
+      goto free_index;
+  }
+
+  if (ret != OID_EXISTS) {
+    char index_str[DATA_MAX_NAME_LEN];
+
+    if (index == NULL)
+      snmp_agent_oid_to_string(index_str, sizeof(index_str), *index_oid);
+    else
+      snprintf(index_str, sizeof(index_str), "%d", *index);
+
+    notification_t n = {
+        .severity = NOTIF_OKAY, .time = cdtime(), .plugin = PLUGIN_NAME};
+    sstrncpy(n.host, hostname_g, sizeof(n.host));
+    snprintf(n.message, sizeof(n.message),
+             "Data added to table %s with index %s", td->name, index_str);
+    DEBUG(PLUGIN_NAME ": %s", n.message);
+
+    plugin_dispatch_notification(&n);
+  }
+
+  if (do_free_index_oid)
+    sfree(*index_oid);
 
   return 0;
+
+free_value:
+  sfree(value);
+unregister_index:
+  if (td->index_oid.oid_len)
+    snmp_agent_unregister_oid_index(*index_oid, *index);
+remove_avl_index:
+  if (td->index_oid.oid_len)
+    c_avl_remove(td->index_instance, index, NULL, NULL);
+remove_avl_index_oid:
+  c_avl_remove(td->instance_index, *index_oid, NULL, NULL);
+free_index:
+  if (index != NULL)
+    sfree(index);
+free_index_oid:
+  sfree(*index_oid);
+
+  return ret;
 }
 
 static int snmp_agent_write(value_list_t const *vl) {
-
   if (vl == NULL)
     return -EINVAL;
 
@@ -1337,11 +2032,22 @@ static int snmp_agent_write(value_list_t const *vl) {
     for (llentry_t *de = llist_head(td->columns); de != NULL; de = de->next) {
       data_definition_t *dd = de->value;
 
-      if (!dd->is_instance) {
+      if (!dd->is_index_key) {
         if (CHECK_DD_TYPE(dd, vl->plugin, vl->plugin_instance, vl->type,
                           vl->type_instance)) {
-          snmp_agent_update_index(td, vl->plugin_instance);
-          return 0;
+          oid_t *index_oid = calloc(1, sizeof(*index_oid));
+
+          if (index_oid == NULL) {
+            ERROR(PLUGIN_NAME ": Could not allocate memory for index_oid");
+            return -ENOMEM;
+          }
+
+          int ret = snmp_agent_generate_index(td, vl, index_oid);
+
+          if (ret == 0)
+            ret = snmp_agent_update_index(dd, td, &index_oid);
+
+          return ret;
         }
       }
     }
@@ -1363,10 +2069,6 @@ static int snmp_agent_collect(const data_set_t *ds, const value_list_t *vl,
 }
 
 static int snmp_agent_preinit(void) {
-  if (g_agent != NULL) {
-    /* already initialized if config callback was called before init callback */
-    return 0;
-  }
 
   g_agent = calloc(1, sizeof(*g_agent));
   if (g_agent == NULL) {
@@ -1376,22 +2078,26 @@ static int snmp_agent_preinit(void) {
 
   g_agent->tables = llist_create();
   g_agent->scalars = llist_create();
+  g_agent->registered_oids =
+      c_avl_create((int (*)(const void *, const void *))oid_compare);
 
   if (g_agent->tables == NULL || g_agent->scalars == NULL) {
     ERROR(PLUGIN_NAME ": llist_create() failed");
     llist_destroy(g_agent->scalars);
     llist_destroy(g_agent->tables);
+    c_avl_destroy(g_agent->registered_oids);
     return -ENOMEM;
   }
 
   int err;
-  /* make us a agentx client. */
+  /* make us an agentx client. */
   err = netsnmp_ds_set_boolean(NETSNMP_DS_APPLICATION_ID, NETSNMP_DS_AGENT_ROLE,
                                1);
   if (err != 0) {
     ERROR(PLUGIN_NAME ": Failed to set agent role (%d)", err);
     llist_destroy(g_agent->scalars);
     llist_destroy(g_agent->tables);
+    c_avl_destroy(g_agent->registered_oids);
     return -1;
   }
 
@@ -1405,6 +2111,7 @@ static int snmp_agent_preinit(void) {
     ERROR(PLUGIN_NAME ": Failed to initialize the agent library (%d)", err);
     llist_destroy(g_agent->scalars);
     llist_destroy(g_agent->tables);
+    c_avl_destroy(g_agent->registered_oids);
     return -1;
   }
 
@@ -1480,6 +2187,27 @@ static void *snmp_agent_thread_run(void __attribute__((unused)) * arg) {
 
 static int snmp_agent_register_oid(oid_t *oid, Netsnmp_Node_Handler *handler) {
   netsnmp_handler_registration *reg;
+
+  if (c_avl_get(g_agent->registered_oids, (void *)oid, NULL) == 0)
+    return OID_EXISTS;
+  else {
+    oid_t *new_oid = calloc(1, sizeof(*oid));
+
+    if (new_oid == NULL) {
+      ERROR(PLUGIN_NAME ": Could not allocate memory to register new OID");
+      return -ENOMEM;
+    }
+
+    memcpy(new_oid, oid, sizeof(*oid));
+
+    int ret = c_avl_insert(g_agent->registered_oids, (void *)new_oid, NULL);
+    if (ret != 0) {
+      ERROR(PLUGIN_NAME ": Could not allocate memory to register new OID");
+      sfree(new_oid);
+      return -ENOMEM;
+    }
+  }
+
   char *oid_name = snmp_agent_get_oid_name(oid->oid, oid->oid_len - 1);
   char oid_str[DATA_MAX_NAME_LEN];
 
@@ -1554,13 +2282,22 @@ static int snmp_agent_shutdown(void) {
   pthread_mutex_destroy(&g_agent->lock);
   pthread_mutex_destroy(&g_agent->agentx_lock);
 
+  /* Freeing registered OIDs list */
+  void *oid;
+
+  if (g_agent->registered_oids != NULL) {
+    while (c_avl_pick(g_agent->registered_oids, &oid, NULL) == 0) {
+      sfree(oid);
+    }
+    c_avl_destroy(g_agent->registered_oids);
+  }
+
   sfree(g_agent);
 
   return ret;
 }
 
 static int snmp_agent_config(oconfig_item_t *ci) {
-
   int ret = snmp_agent_preinit();
 
   if (ret != 0) {
@@ -1571,7 +2308,7 @@ static int snmp_agent_config(oconfig_item_t *ci) {
   for (int i = 0; i < ci->children_num; i++) {
     oconfig_item_t *child = ci->children + i;
     if (strcasecmp("Data", child->key) == 0) {
-      ret = snmp_agent_config_data(child);
+      ret = snmp_agent_config_scalar(child);
     } else if (strcasecmp("Table", child->key) == 0) {
       ret = snmp_agent_config_table(child);
     } else {
@@ -1588,7 +2325,7 @@ static int snmp_agent_config(oconfig_item_t *ci) {
     }
   }
 
-  ret = snmp_agent_validate_data();
+  ret = snmp_agent_validate_config();
   if (ret != 0) {
     ERROR(PLUGIN_NAME ": Invalid configuration provided");
     snmp_agent_free_config();
diff --git a/src/snmp_agent_test.c b/src/snmp_agent_test.c
new file mode 100644
index 00000000..68389fa9
--- /dev/null
+++ b/src/snmp_agent_test.c
@@ -0,0 +1,825 @@
+/**
+ * collectd - src/snmp_agent_test.c
+ *
+ * Copyright(c) 2017 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:
+ *   Marcin Mozejko <marcinx.mozejko@intel.com>
+ **/
+
+#include "snmp_agent.c"
+#include "testing.h"
+
+#define TEST_HOSTNAME "test_hostname"
+#define TEST_PLUGIN "test_plugin"
+#define TEST_PLUGIN_INST "test_plugin_inst"
+#define TEST_TYPE "test_type"
+#define TEST_TYPE_INST "test_type_inst"
+
+DEF_TEST(oid_to_string) {
+  oid_t o = {.oid = {1, 2, 3, 4, 5, 6, 7, 8, 9}, .oid_len = 9};
+  char oid_str[DATA_MAX_NAME_LEN];
+
+  int ret = snmp_agent_oid_to_string(oid_str, DATA_MAX_NAME_LEN, &o);
+  EXPECT_EQ_INT(o.oid_len * 2 - 1, ret);
+  EXPECT_EQ_STR("1.2.3.4.5.6.7.8.9", oid_str);
+
+  return 0;
+}
+
+/* Testing formatting metric name for simple scalar */
+DEF_TEST(format_name_scalar) {
+  data_definition_t *dd = calloc(1, sizeof(*dd));
+
+  dd->plugin = TEST_PLUGIN;
+  dd->plugin_instance = TEST_PLUGIN_INST;
+  dd->type = TEST_TYPE;
+  dd->type_instance = TEST_TYPE_INST;
+
+  char name[DATA_MAX_NAME_LEN];
+  int ret = snmp_agent_format_name(name, sizeof(name), dd, NULL);
+
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR(
+      "example.com/test_plugin-test_plugin_inst/test_type-test_type_inst",
+      name);
+
+  sfree(dd);
+
+  return 0;
+}
+
+DEF_TEST(format_name_simple_index) {
+  netsnmp_variable_list *index_list_tmp = NULL;
+  oid_t index_oid;
+  data_definition_t *dd = calloc(1, sizeof(*dd));
+  table_definition_t *td = calloc(1, sizeof(*td));
+
+  td->index_list_cont = NULL;
+  td->index_keys[0].source = INDEX_PLUGIN_INSTANCE;
+  td->index_keys[0].type = ASN_OCTET_STR;
+  td->index_keys[1].source = INDEX_TYPE_INSTANCE;
+  td->index_keys[1].type = ASN_OCTET_STR;
+  dd->table = td;
+  dd->plugin = TEST_PLUGIN;
+  dd->type = TEST_TYPE;
+
+  const char plugin_inst[] = TEST_PLUGIN_INST;
+  const char type_inst[] = TEST_TYPE_INST;
+
+  snmp_varlist_add_variable(&index_list_tmp, NULL, 0, ASN_OCTET_STR,
+                            (const u_char *)plugin_inst, strlen(plugin_inst));
+  snmp_varlist_add_variable(&index_list_tmp, NULL, 0, ASN_OCTET_STR,
+                            (const u_char *)type_inst, strlen(type_inst));
+
+  build_oid_noalloc(index_oid.oid, sizeof(index_oid.oid), &index_oid.oid_len,
+                    NULL, 0, index_list_tmp);
+
+  snmp_varlist_add_variable(&td->index_list_cont, NULL, 0, ASN_OCTET_STR, NULL,
+                            0);
+  snmp_varlist_add_variable(&td->index_list_cont, NULL, 0, ASN_OCTET_STR, NULL,
+                            0);
+
+  char name[DATA_MAX_NAME_LEN];
+
+  int ret = snmp_agent_format_name(name, DATA_MAX_NAME_LEN, dd, &index_oid);
+
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR(
+      "example.com/test_plugin-test_plugin_inst/test_type-test_type_inst",
+      name);
+
+  snmp_free_varbind(index_list_tmp);
+  snmp_free_varbind(td->index_list_cont);
+  sfree(dd);
+  sfree(td);
+
+  return 0;
+}
+
+DEF_TEST(format_name_regex_index) {
+  netsnmp_variable_list *index_list_tmp = NULL;
+  oid_t index_oid;
+  data_definition_t *dd = calloc(1, sizeof(*dd));
+  table_definition_t *td = calloc(1, sizeof(*td));
+
+  td->index_keys_len = 3;
+  td->index_list_cont = NULL;
+  td->index_keys[0].source = INDEX_PLUGIN_INSTANCE;
+  td->index_keys[0].type = ASN_OCTET_STR;
+  td->index_keys[1].source = INDEX_TYPE_INSTANCE;
+  td->index_keys[1].type = ASN_INTEGER;
+  td->index_keys[1].regex = "^vcpu_([0-9]{1,3})-cpu_[0-9]{1,3}$";
+  td->index_keys[1].group = 1;
+  td->index_keys[2].source = INDEX_TYPE_INSTANCE;
+  td->index_keys[2].type = ASN_INTEGER;
+  td->index_keys[2].regex = "^vcpu_[0-9]{1,3}-cpu_([0-9]{1,3})$";
+  td->index_keys[2].group = 1;
+
+  dd->table = td;
+  dd->plugin = TEST_PLUGIN;
+  dd->type = TEST_TYPE;
+
+  const char plugin_inst[] = TEST_PLUGIN_INST;
+  int vcpu = 1;
+  int cpu = 10;
+
+  snmp_varlist_add_variable(&index_list_tmp, NULL, 0, ASN_OCTET_STR,
+                            (const u_char *)plugin_inst, strlen(plugin_inst));
+  snmp_varlist_add_variable(&index_list_tmp, NULL, 0, ASN_INTEGER,
+                            (const u_char *)&vcpu, 1);
+  snmp_varlist_add_variable(&index_list_tmp, NULL, 0, ASN_INTEGER,
+                            (const u_char *)&cpu, 1);
+
+  build_oid_noalloc(index_oid.oid, sizeof(index_oid.oid), &index_oid.oid_len,
+                    NULL, 0, index_list_tmp);
+
+  token_t *token;
+  int *offset;
+
+  td->tokens[INDEX_TYPE_INSTANCE] =
+      c_avl_create((int (*)(const void *, const void *))num_compare);
+  snmp_varlist_add_variable(&td->index_list_cont, NULL, 0, ASN_OCTET_STR, NULL,
+                            0);
+
+  token = malloc(sizeof(*token));
+  offset = malloc(sizeof(*offset));
+  token->key = snmp_varlist_add_variable(&td->index_list_cont, NULL, 0,
+                                         ASN_INTEGER, NULL, 0);
+  token->str = strdup("vcpu_");
+  *offset = 0;
+  int ret = c_avl_insert(td->tokens[INDEX_TYPE_INSTANCE], (void *)offset,
+                         (void *)token);
+
+  token = malloc(sizeof(*token));
+  offset = malloc(sizeof(*offset));
+  token->key = snmp_varlist_add_variable(&td->index_list_cont, NULL, 0,
+                                         ASN_INTEGER, NULL, 0);
+  token->str = strdup("-cpu_");
+  *offset = 6;
+  ret += c_avl_insert(td->tokens[INDEX_TYPE_INSTANCE], (void *)offset,
+                      (void *)token);
+  char name[DATA_MAX_NAME_LEN];
+
+  ret += snmp_agent_format_name(name, DATA_MAX_NAME_LEN, dd, &index_oid);
+
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR(
+      "example.com/test_plugin-test_plugin_inst/test_type-vcpu_1-cpu_10", name);
+  while (c_avl_pick(td->tokens[INDEX_TYPE_INSTANCE], (void **)&offset,
+                    (void **)&token) == 0) {
+    sfree(offset);
+    sfree(token->str);
+    sfree(token);
+  }
+  c_avl_destroy(td->tokens[INDEX_TYPE_INSTANCE]);
+  snmp_free_varbind(index_list_tmp);
+  snmp_free_varbind(td->index_list_cont);
+  sfree(dd);
+  sfree(td);
+
+  return 0;
+}
+
+DEF_TEST(prep_index_list) {
+  table_definition_t *td = calloc(1, sizeof(*td));
+
+  assert(td != NULL);
+  td->index_keys_len = 5;
+  td->index_keys[0].source = INDEX_HOST;
+  td->index_keys[0].type = ASN_OCTET_STR;
+  td->index_keys[1].source = INDEX_PLUGIN;
+  td->index_keys[1].type = ASN_OCTET_STR;
+  td->index_keys[2].source = INDEX_PLUGIN_INSTANCE;
+  td->index_keys[2].type = ASN_INTEGER;
+  td->index_keys[3].source = INDEX_TYPE;
+  td->index_keys[3].type = ASN_INTEGER;
+  td->index_keys[4].source = INDEX_TYPE_INSTANCE;
+  td->index_keys[4].type = ASN_OCTET_STR;
+  td->index_list_cont = NULL;
+
+  int ret = snmp_agent_prep_index_list(td, &td->index_list_cont);
+  EXPECT_EQ_INT(0, ret);
+
+  netsnmp_variable_list *key = td->index_list_cont;
+
+  OK(key != NULL);
+  EXPECT_EQ_INT(ASN_OCTET_STR, key->type);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_INT(ASN_OCTET_STR, key->type);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_INT(ASN_INTEGER, key->type);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_INT(ASN_INTEGER, key->type);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_INT(ASN_OCTET_STR, key->type);
+  key = key->next_variable;
+  OK(key == NULL);
+
+  snmp_free_varbind(td->index_list_cont);
+  sfree(td);
+
+  return 0;
+}
+
+DEF_TEST(fill_index_list_simple) {
+  table_definition_t *td = calloc(1, sizeof(*td));
+  assert(td != NULL);
+
+  /* Preparing value list */
+  value_list_t *vl = calloc(1, sizeof(*vl));
+  assert(vl != NULL);
+  strncpy(vl->host, TEST_HOSTNAME, DATA_MAX_NAME_LEN);
+  strncpy(vl->plugin, TEST_PLUGIN, DATA_MAX_NAME_LEN);
+  strncpy(vl->plugin_instance, TEST_PLUGIN_INST, DATA_MAX_NAME_LEN);
+  strncpy(vl->type, TEST_TYPE, DATA_MAX_NAME_LEN);
+  strncpy(vl->type_instance, TEST_TYPE_INST, DATA_MAX_NAME_LEN);
+
+  td->index_keys_len = 5;
+  td->index_keys[0].source = INDEX_HOST;
+  td->index_keys[0].type = ASN_OCTET_STR;
+  td->index_keys[1].source = INDEX_PLUGIN;
+  td->index_keys[1].type = ASN_OCTET_STR;
+  td->index_keys[2].source = INDEX_PLUGIN_INSTANCE;
+  td->index_keys[2].type = ASN_OCTET_STR;
+  td->index_keys[3].source = INDEX_TYPE;
+  td->index_keys[3].type = ASN_OCTET_STR;
+  td->index_keys[4].source = INDEX_TYPE_INSTANCE;
+  td->index_keys[4].type = ASN_OCTET_STR;
+
+  td->index_list_cont = NULL;
+  for (int i = 0; i < td->index_keys_len; i++)
+    snmp_varlist_add_variable(&td->index_list_cont, NULL, 0, ASN_OCTET_STR,
+                              NULL, 0);
+
+  int ret = snmp_agent_fill_index_list(td, vl);
+  EXPECT_EQ_INT(0, ret);
+
+  netsnmp_variable_list *key = td->index_list_cont;
+
+  ret = 0;
+
+  OK(key != NULL);
+  EXPECT_EQ_STR(vl->host, (char *)key->val.string);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_STR(vl->plugin, (char *)key->val.string);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_STR(vl->plugin_instance, (char *)key->val.string);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_STR(vl->type, (char *)key->val.string);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_STR(vl->type_instance, (char *)key->val.string);
+  key = key->next_variable;
+  OK(key == NULL);
+
+  snmp_free_varbind(td->index_list_cont);
+  sfree(vl);
+  sfree(td);
+
+  return 0;
+}
+
+DEF_TEST(fill_index_list_regex) {
+  table_definition_t *td = calloc(1, sizeof(*td));
+  int ret = 0;
+
+  assert(td != NULL);
+
+  /* Preparing value list */
+  value_list_t *vl = calloc(1, sizeof(*vl));
+  strncpy(vl->plugin_instance, TEST_PLUGIN_INST, DATA_MAX_NAME_LEN);
+  strncpy(vl->type_instance, "1test2test3", DATA_MAX_NAME_LEN);
+
+  td->index_keys_len = 4;
+  td->index_keys[0].source = INDEX_PLUGIN_INSTANCE;
+  td->index_keys[0].type = ASN_OCTET_STR;
+  td->index_keys[1].source = INDEX_TYPE_INSTANCE;
+  td->index_keys[1].type = ASN_INTEGER;
+  td->index_keys[1].regex = "^([0-9])test[0-9]test[0-9]$";
+  td->index_keys[1].group = 1;
+  td->index_keys[2].source = INDEX_TYPE_INSTANCE;
+  td->index_keys[2].type = ASN_INTEGER;
+  td->index_keys[2].regex = "^[0-9]test([0-9])test[0-9]$";
+  td->index_keys[2].group = 1;
+  td->index_keys[3].source = INDEX_TYPE_INSTANCE;
+  td->index_keys[3].type = ASN_INTEGER;
+  td->index_keys[3].regex = "^[0-9]test[0-9]test([0-9])$";
+  td->index_keys[3].group = 1;
+
+  td->index_list_cont = NULL;
+  snmp_varlist_add_variable(&td->index_list_cont, NULL, 0, ASN_OCTET_STR, NULL,
+                            0);
+  for (int i = 1; i < td->index_keys_len; i++) {
+    snmp_varlist_add_variable(&td->index_list_cont, NULL, 0, ASN_INTEGER, NULL,
+                              0);
+    ret = regcomp(&td->index_keys[i].regex_info, td->index_keys[i].regex,
+                  REG_EXTENDED);
+    EXPECT_EQ_INT(0, ret);
+  }
+  td->tokens[INDEX_TYPE_INSTANCE] =
+      c_avl_create((int (*)(const void *, const void *))num_compare);
+  assert(td->tokens[INDEX_TYPE_INSTANCE] != NULL);
+
+  ret = snmp_agent_fill_index_list(td, vl);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(1, td->tokens_done);
+
+  netsnmp_variable_list *key = td->index_list_cont;
+
+  OK(key != NULL);
+  EXPECT_EQ_STR(vl->plugin_instance, (char *)key->val.string);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_INT(1, *key->val.integer);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_INT(2, *key->val.integer);
+  key = key->next_variable;
+  OK(key != NULL);
+  EXPECT_EQ_INT(3, *key->val.integer);
+  key = key->next_variable;
+  OK(key == NULL);
+
+  token_t *token;
+  int *offset;
+
+  while (c_avl_pick(td->tokens[INDEX_TYPE_INSTANCE], (void **)&offset,
+                    (void **)&token) == 0) {
+    sfree(offset);
+    sfree(token->str);
+    sfree(token);
+  }
+
+  c_avl_destroy(td->tokens[INDEX_TYPE_INSTANCE]);
+  snmp_free_varbind(td->index_list_cont);
+  sfree(vl);
+
+  for (int i = 0; i < td->index_keys_len; i++) {
+    regfree(&td->index_keys[i].regex_info);
+  }
+  sfree(td);
+
+  return 0;
+}
+
+DEF_TEST(config_index_key_source) {
+  oconfig_item_t *ci = calloc(1, sizeof(*ci));
+  table_definition_t *td = calloc(1, sizeof(*td));
+  data_definition_t *dd = calloc(1, sizeof(*dd));
+
+  assert(ci != NULL);
+  assert(td != NULL);
+  assert(dd != NULL);
+
+  ci->values = calloc(1, sizeof(*ci->values));
+  assert(ci->values != NULL);
+  ci->values_num = 1;
+  ci->values->value.string = "PluginInstance";
+  ci->values->type = OCONFIG_TYPE_STRING;
+
+  int ret = snmp_agent_config_index_key_source(td, dd, ci);
+
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(1, td->index_keys_len);
+  EXPECT_EQ_INT(0, dd->index_key_pos);
+  EXPECT_EQ_INT(INDEX_PLUGIN_INSTANCE, td->index_keys[0].source);
+  EXPECT_EQ_INT(GROUP_UNUSED, td->index_keys[0].group);
+  OK(td->index_keys[0].regex == NULL);
+
+  sfree(ci->values);
+  sfree(ci);
+  sfree(td);
+  sfree(dd);
+
+  return 0;
+}
+
+DEF_TEST(config_index_key_regex) {
+  oconfig_item_t *ci = calloc(1, sizeof(*ci));
+  table_definition_t *td = calloc(1, sizeof(*td));
+  data_definition_t *dd = calloc(1, sizeof(*dd));
+
+  assert(ci != NULL);
+  assert(td != NULL);
+  assert(dd != NULL);
+
+  dd->index_key_pos = 0;
+  td->index_keys_len = 1;
+  td->index_keys[0].source = INDEX_PLUGIN_INSTANCE;
+  td->index_keys[0].group = 1;
+  ci->values = calloc(1, sizeof(*ci->values));
+  assert(ci->values != NULL);
+  ci->values_num = 1;
+  ci->values->value.string = "^([0-9])test[0-9]test[0-9]$";
+  ci->values->type = OCONFIG_TYPE_STRING;
+
+  int ret = snmp_agent_config_index_key_regex(td, dd, ci);
+
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR(td->index_keys[0].regex, "^([0-9])test[0-9]test[0-9]$");
+  OK(td->tokens[INDEX_PLUGIN_INSTANCE] != NULL);
+
+  c_avl_destroy(td->tokens[INDEX_PLUGIN_INSTANCE]);
+  sfree(ci->values);
+  sfree(ci);
+  sfree(td->index_keys[0].regex);
+  regfree(&td->index_keys[0].regex_info);
+  sfree(td);
+  sfree(dd);
+
+  return 0;
+}
+
+DEF_TEST(config_index_key) {
+  oconfig_item_t *ci = calloc(1, sizeof(*ci));
+  table_definition_t *td = calloc(1, sizeof(*td));
+  data_definition_t *dd = calloc(1, sizeof(*dd));
+
+  assert(ci != NULL);
+  assert(td != NULL);
+  assert(dd != NULL);
+
+  ci->children_num = 3;
+  ci->children = calloc(1, sizeof(*ci->children) * ci->children_num);
+
+  ci->children[0].key = "Source";
+  ci->children[0].parent = ci;
+  ci->children[0].values_num = 1;
+  ci->children[0].values = calloc(1, sizeof(*ci->children[0].values));
+  assert(ci->children[0].values != NULL);
+  ci->children[0].values->value.string = "PluginInstance";
+  ci->children[0].values->type = OCONFIG_TYPE_STRING;
+
+  ci->children[1].key = "Regex";
+  ci->children[1].parent = ci;
+  ci->children[1].values_num = 1;
+  ci->children[1].values = calloc(1, sizeof(*ci->children[0].values));
+  assert(ci->children[1].values != NULL);
+  ci->children[1].values->value.string = "^([0-9])test[0-9]test[0-9]$";
+  ci->children[1].values->type = OCONFIG_TYPE_STRING;
+
+  ci->children[2].key = "Group";
+  ci->children[2].parent = ci;
+  ci->children[2].values_num = 1;
+  ci->children[2].values = calloc(1, sizeof(*ci->children[0].values));
+  assert(ci->children[2].values != NULL);
+  ci->children[2].values->value.number = 1;
+  ci->children[2].values->type = OCONFIG_TYPE_NUMBER;
+
+  int ret = snmp_agent_config_index_key(td, dd, ci);
+
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(1, td->index_keys_len);
+  EXPECT_EQ_INT(0, dd->index_key_pos);
+  EXPECT_EQ_INT(INDEX_PLUGIN_INSTANCE, td->index_keys[0].source);
+  EXPECT_EQ_INT(1, td->index_keys[0].group);
+  EXPECT_EQ_STR("^([0-9])test[0-9]test[0-9]$", td->index_keys[0].regex);
+  OK(td->tokens[INDEX_PLUGIN_INSTANCE] != NULL);
+
+  sfree(ci->children[0].values);
+  sfree(ci->children[1].values);
+  sfree(ci->children[2].values);
+
+  sfree(ci->children);
+  sfree(ci);
+
+  c_avl_destroy(td->tokens[INDEX_PLUGIN_INSTANCE]);
+  sfree(dd);
+  sfree(td->index_keys[0].regex);
+  regfree(&td->index_keys[0].regex_info);
+  sfree(td);
+
+  return 0;
+}
+
+DEF_TEST(parse_index_key) {
+  const char regex[] = "test-([0-9])-([0-9])";
+  const char input[] = "snmp-test-5-6";
+  regex_t regex_info;
+  regmatch_t match;
+
+  int ret = regcomp(&regex_info, regex, REG_EXTENDED);
+  EXPECT_EQ_INT(0, ret);
+
+  ret = snmp_agent_parse_index_key(input, &regex_info, 0, &match);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(5, match.rm_so);
+  EXPECT_EQ_INT(13, match.rm_eo);
+
+  ret = snmp_agent_parse_index_key(input, &regex_info, 1, &match);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(10, match.rm_so);
+  EXPECT_EQ_INT(11, match.rm_eo);
+
+  ret = snmp_agent_parse_index_key(input, &regex_info, 2, &match);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(12, match.rm_so);
+  EXPECT_EQ_INT(13, match.rm_eo);
+
+  regfree(&regex_info);
+
+  return 0;
+}
+
+DEF_TEST(create_token) {
+  c_avl_tree_t *tokens =
+      c_avl_create((int (*)(const void *, const void *))num_compare);
+  const char input[] = "testA1-testB2";
+
+  assert(tokens != NULL);
+
+  int ret = snmp_agent_create_token(input, 0, 5, tokens, NULL);
+  EXPECT_EQ_INT(0, ret);
+  ret = snmp_agent_create_token(input, 6, 6, tokens, NULL);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(2, c_avl_size(tokens));
+
+  token_t *token;
+  int *offset;
+
+  ret = c_avl_pick(tokens, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(6, *offset);
+  EXPECT_EQ_STR("-testB", token->str);
+  sfree(offset);
+  sfree(token->str);
+  sfree(token);
+
+  ret = c_avl_pick(tokens, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(0, *offset);
+  EXPECT_EQ_STR("testA", token->str);
+  sfree(offset);
+  sfree(token->str);
+  sfree(token);
+
+  ret = c_avl_pick(tokens, (void **)&offset, (void **)&token);
+  OK(ret != 0);
+
+  c_avl_destroy(tokens);
+
+  return 0;
+}
+
+DEF_TEST(delete_token) {
+  c_avl_tree_t *tokens =
+      c_avl_create((int (*)(const void *, const void *))num_compare);
+  const char input[] = "testA1-testB2-testC3";
+
+  assert(tokens != NULL);
+
+  int ret = snmp_agent_create_token(input, 0, 5, tokens, NULL);
+  EXPECT_EQ_INT(0, ret);
+  ret = snmp_agent_create_token(input, 6, 6, tokens, NULL);
+  EXPECT_EQ_INT(0, ret);
+  ret = snmp_agent_create_token(input, 13, 6, tokens, NULL);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(3, c_avl_size(tokens));
+  ret = snmp_agent_delete_token(6, tokens);
+  EXPECT_EQ_INT(0, ret);
+
+  token_t *token;
+  int *offset;
+
+  ret = c_avl_pick(tokens, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(0, *offset);
+  EXPECT_EQ_STR("testA", token->str);
+  sfree(offset);
+  sfree(token->str);
+  sfree(token);
+
+  ret = c_avl_pick(tokens, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(13, *offset);
+  EXPECT_EQ_STR("-testC", token->str);
+  sfree(offset);
+  sfree(token->str);
+  sfree(token);
+
+  ret = c_avl_pick(tokens, (void **)&offset, (void **)&token);
+  OK(ret != 0);
+
+  c_avl_destroy(tokens);
+
+  return 0;
+}
+
+DEF_TEST(get_token) {
+  c_avl_tree_t *tokens =
+      c_avl_create((int (*)(const void *, const void *))num_compare);
+  const char input[] = "testA1-testB2-testC3";
+
+  assert(tokens != NULL);
+
+  int ret = snmp_agent_create_token(input, 0, 5, tokens, NULL);
+  EXPECT_EQ_INT(0, ret);
+  ret = snmp_agent_create_token(input, 6, 6, tokens, NULL);
+  EXPECT_EQ_INT(0, ret);
+  ret = snmp_agent_create_token(input, 13, 6, tokens, NULL);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_INT(3, c_avl_size(tokens));
+  ret = snmp_agent_get_token(tokens, 12);
+  EXPECT_EQ_INT(6, ret);
+
+  token_t *token;
+  int *offset;
+
+  while (c_avl_pick(tokens, (void **)&offset, (void **)&token) == 0) {
+    sfree(offset);
+    sfree(token->str);
+    sfree(token);
+  }
+
+  c_avl_destroy(tokens);
+
+  return 0;
+}
+
+DEF_TEST(tokenize) {
+  regmatch_t m[3] = {{5, 6},    /* "1" */
+                     {12, 13},  /* "2" */
+                     {19, 20}}; /* "3" */
+  c_avl_tree_t *tokens =
+      c_avl_create((int (*)(const void *, const void *))num_compare);
+  const char input[] = "testA1-testB2-testC3";
+  token_t *token;
+  int *offset;
+  c_avl_iterator_t *it;
+  int ret;
+
+  assert(tokens != NULL);
+
+  /* First pass */
+  ret = snmp_agent_tokenize(input, tokens, &m[0], NULL);
+  EXPECT_EQ_INT(0, ret);
+  it = c_avl_get_iterator(tokens);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR("testA", token->str);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR("-testB2-testC3", token->str);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  OK(ret != 0);
+  c_avl_iterator_destroy(it);
+
+  /* Second pass */
+  ret = snmp_agent_tokenize(input, tokens, &m[1], NULL);
+  EXPECT_EQ_INT(0, ret);
+  it = c_avl_get_iterator(tokens);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR("testA", token->str);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR("-testB", token->str);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR("-testC3", token->str);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  OK(ret != 0);
+  c_avl_iterator_destroy(it);
+
+  /* Third pass */
+  ret = snmp_agent_tokenize(input, tokens, &m[2], NULL);
+  EXPECT_EQ_INT(0, ret);
+  it = c_avl_get_iterator(tokens);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR("testA", token->str);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR("-testB", token->str);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR("-testC", token->str);
+  ret = c_avl_iterator_next(it, (void **)&offset, (void **)&token);
+  OK(ret != 0);
+  c_avl_iterator_destroy(it);
+
+  while (c_avl_pick(tokens, (void **)&offset, (void **)&token) == 0) {
+    sfree(offset);
+    sfree(token->str);
+    sfree(token);
+  }
+
+  c_avl_destroy(tokens);
+
+  return 0;
+}
+
+DEF_TEST(build_name) {
+  table_definition_t *td = calloc(1, sizeof(*td));
+  c_avl_tree_t *tokens =
+      c_avl_create((int (*)(const void *, const void *))num_compare);
+
+  assert(tokens != NULL);
+  assert(td != NULL);
+
+  int n[3] = {1, 2, 3};
+  char *t[3] = {"testA", "-testB", "-testC"};
+  int off[3] = {0, 6, 13};
+  token_t *token;
+  int *offset;
+  int ret = 0;
+  char *name = NULL;
+
+  td->index_list_cont = NULL;
+  for (int i = 0; i < 3; i++) {
+    token = malloc(sizeof(*token));
+    token->str = t[i];
+    token->key =
+        snmp_varlist_add_variable(&td->index_list_cont, NULL, 0, ASN_INTEGER,
+                                  (const u_char *)&n[i], sizeof(n[i]));
+    assert(token->key != NULL);
+    offset = &off[i];
+    ret = c_avl_insert(tokens, (void *)offset, (void *)token);
+    assert(ret == 0);
+  }
+
+  ret = snmp_agent_build_name(&name, tokens);
+  EXPECT_EQ_INT(0, ret);
+  EXPECT_EQ_STR("testA1-testB2-testC3", name);
+
+  while (c_avl_pick(tokens, (void **)&offset, (void **)&token) == 0)
+    sfree(token);
+
+  c_avl_destroy(tokens);
+  snmp_free_varbind(td->index_list_cont);
+  sfree(td);
+  sfree(name);
+  return 0;
+}
+
+int main(void) {
+  /* snmp_agent_oid_to_string */
+  RUN_TEST(oid_to_string);
+
+  /* snmp_agent_prep_index_list */
+  RUN_TEST(prep_index_list);
+
+  /* snmp_agent_fill_index_list */
+  RUN_TEST(fill_index_list_simple);
+  RUN_TEST(fill_index_list_regex);
+
+  /* snmp_agent_format_name */
+  RUN_TEST(format_name_scalar);
+  RUN_TEST(format_name_simple_index);
+  RUN_TEST(format_name_regex_index);
+
+  /* snmp_agent_config_index_key_source */
+  RUN_TEST(config_index_key_source);
+
+  /* snmp_agent_config_index_key_regex */
+  RUN_TEST(config_index_key_regex);
+
+  /* snmp_agent_config_index_key */
+  RUN_TEST(config_index_key);
+
+  /*snmp_agent_parse_index_key */
+  RUN_TEST(parse_index_key);
+
+  /* snmp_agent_create_token */
+  RUN_TEST(create_token);
+
+  /* snmp_agent_delete_token */
+  RUN_TEST(delete_token);
+
+  /* snmp_agent_get_token */
+  RUN_TEST(get_token);
+
+  /* snmp_agent_tokenize */
+  RUN_TEST(tokenize);
+
+  /* snmp_agent_build_name */
+  RUN_TEST(build_name);
+
+  END_TEST;
+}