Added TCP Packets issues check (#6899)

scripts/lua/modules/check_definitions/flow/tcp_packets_issues.lua

@@ -0,0 +1,57 @@
+--
+-- (C) 2019-22 - ntop.org
+--
+
+local checks = require ("checks")
+local alerts_api = require "alerts_api"
+local alert_consts = require("alert_consts")
+local flow_alert_keys = require "flow_alert_keys"
+
+-- #################################################################
+
+-- NOTE: this module is always enabled
+local script = {
+  -- Script category
+  category = checks.check_categories.network,
+  enabled = false,
+
+  -- This script is only for alerts generation
+  alert_id = flow_alert_keys.flow_alert_tcp_packets_issues,
+
+  default_value = {
+    retransmissions = {
+      default_value = 15, -- 15%,
+      field_min = 0, -- 0%
+      field_max = 99, -- 99%
+      field_operator = "gt";
+      i18n_fields_unit = checks.field_units.percentage,
+      title = i18n('retransmission')
+    },
+    out_of_orders = {
+      default_value = 15, -- 15%,
+      field_min = 0, -- 0%
+      field_max = 99, -- 99%
+      field_operator = "gt";
+      i18n_fields_unit = checks.field_units.percentage,
+      title = i18n('out_of_order')
+    },
+    packet_loss = {
+      default_value = 15, -- 15%,
+      field_min = 0, -- 0%
+      field_max = 99, -- 99%
+      field_operator = "gt";
+      i18n_fields_unit = checks.field_units.percentage,
+      title = i18n('packet_loss')
+    },
+  },
+
+  gui = {
+    i18n_title = "flow_checks_config.tcp_packets_issues",
+    i18n_description = "flow_checks_config.tcp_packets_issues_description",
+    input_builder = "multi_threshold_cross",
+  }
+}
+
+-- #################################################################
+
+return script