#! /usr/bin/env stap

global packets

// Set up the metrics
probe begin
{
  // Set the prefix to be used instead of the module name (optional).
  json_set_prefix("netfilter")

  // Add the metrics
  json_add_array("netfilter_data",
		 "Network data indexed by source and destination addresses.")
  json_add_array_numeric_metric("netfilter_data", "packets",
				"Number of packets transferred.", "")
  json_add_array_numeric_metric("netfilter_data", "bytes","Bytes transferred.",
				"bytes")
}

probe netfilter.ipv4.pre_routing {
      // Using aggregates avoids contention from packets being sent in
      // parallel from different processors:
      packets[saddr, daddr] <<< length
}

probe json_data
{
  @json_output_data_start

  foreach ([saddr, daddr] in packets-) {
    index = sprintf("%15s --> %15s", saddr, daddr)
    @json_output_array_numeric_value("netfilter_data", index, "packets",
				     @count(packets[saddr,daddr]))
    @json_output_array_numeric_value("netfilter_data", index, "bytes",
				     @sum(packets[saddr,daddr]))
  }
  @json_output_data_end
}