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#!/usr/bin/env dnsjit
local pcap = arg[2]
local rcode = tonumber(arg[3])
if pcap == nil or rcode == nil then
print("usage: "..arg[1].." <pcap> <rcode>")
return
end
local object = require("dnsjit.core.objects")
local input = require("dnsjit.input.pcap").new()
local layer = require("dnsjit.filter.layer").new()
local dns = require("dnsjit.core.object.dns").new()
input:open_offline(pcap)
layer:producer(input)
local producer, ctx = layer:produce()
while true do
local obj = producer(ctx)
if obj == nil then break end
local pl = obj:cast()
if obj:type() == "payload" and pl.len > 0 then
local transport = obj.obj_prev
while transport ~= nil do
if transport.obj_type == object.IP or transport.obj_type == object.IP6 then
break
end
transport = transport.obj_prev
end
local protocol = obj.obj_prev
while protocol ~= nil do
if protocol.obj_type == object.UDP or protocol.obj_type == object.TCP then
break
end
protocol = protocol.obj_prev
end
dns:reset()
if protocol ~= nil and protocol.obj_type == object.TCP then
dns.includes_dnslen = 1
end
dns.obj_prev = obj
if transport ~= nil and dns:parse_header() == 0 and dns.have_rcode == 1 and dns.rcode == rcode then
transport = transport:cast()
print(dns.id, transport:source().." -> "..transport:destination())
end
end
end
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