Added TCP Packets issues check (#6899)

scripts/lua/modules/alert_definitions/flow/alert_packets_issues.lua

@@ -0,0 +1,63 @@
+--
+-- (C) 2019-22 - ntop.org
+--
+
+-- ##############################################
+
+local flow_alert_keys = require "flow_alert_keys"
+-- Import the classes library.
+local classes = require "classes"
+-- Make sure to import the Superclass!
+local alert = require "alert"
+
+-- ##############################################
+
+local alert_tcp_packets_issues = classes.class(alert)
+
+-- ##############################################
+
+alert_tcp_packets_issues.meta = {
+  alert_key = flow_alert_keys.flow_alert_tcp_packets_issues,
+  i18n_title = "flow_checks_config.tcp_packets_issues",
+  icon = "fas fa-fw fa-exclamation",
+}
+
+-- ##############################################
+
+-- @brief Prepare an alert table used to generate the alert
+-- @param tcp_stats A lua table with TCP stats obtained with flow.getTCPStats
+-- @param cli2srv_pkts Number of packets sent from the client to the server
+-- @param srv2cli_pkts Number of packets sent from the server to the client
+-- @param is_severe A boolean indicating whether connection issues are severe
+-- @param client_issues A boolean indicating if the client has connection issues
+-- @param server_issues A boolean indicating if the server has connection issues
+-- @return A table with the alert built
+function alert_tcp_packets_issues:init()
+  -- Call the parent constructor
+  self.super:init()
+end
+
+-- #######################################################
+
+-- @brief Format an alert into a human-readable string
+-- @param ifid The integer interface id of the generated alert
+-- @param alert The alert description table, including alert data such as the generating entity, timestamp, granularity, type
+-- @param alert_type_params Table `alert_type_params` as built in the `:init` method
+-- @return A human-readable string
+function alert_tcp_packets_issues.format(ifid, alert, alert_type_params)
+  local msg = ''
+  tprint(alert_type_params)
+  if alert_type_params.lost > alert_type_params.lost_threshold then
+    msg = i18n("flow_checks_config.tcp_packets_issues_alert", { type = 'loss', value = alert_type_params.lost, threshold = alert_type_params.lost_threshold })
+  elseif alert_type_params.retransmission > alert_type_params.retransmission_threshold then
+    msg = i18n("flow_checks_config.tcp_packets_issues_alert", { type = 'retransmission', value = alert_type_params.retransmission, threshold = alert_type_params.retransmission_threshold })
+  elseif alert_type_params.out_of_order > alert_type_params.out_of_order_threshold then
+    msg = i18n("flow_checks_config.tcp_packets_issues_alert", { type = 'out of order', value = alert_type_params.out_of_order, threshold = alert_type_params.out_of_order_threshold })
+  end
+
+  return msg
+end
+
+-- #######################################################
+
+return alert_tcp_packets_issues