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#!/usr/bin/env dnsjit
local pcap = arg[2]
if pcap == nil then
print("usage: "..arg[1].." <pcap>")
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()
local label = require("dnsjit.core.object.dns.label")
local ffi = require("ffi")
local labels = require("dnsjit.core.object.dns.label").new(16)
local q = require("dnsjit.core.object.dns.q").new()
input:open_offline(pcap)
layer:producer(input)
local producer, ctx = layer:produce()
local queries = {}
local responses = {}
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.obj_prev = obj
if transport ~= nil and protocol ~= nil and dns:parse_header() == 0 then
transport = transport:cast()
protocol = protocol:cast()
if dns.qr == 1 then
table.insert(responses, {
src = transport:source(),
sport = protocol.sport,
dst = transport:destination(),
dport = protocol.dport,
id = dns.id,
rcode = dns.rcode_tostring(dns.rcode),
})
else
if dns.qdcount > 0 and dns:parse_q(q, labels, 16) == 0 then
table.insert(queries, {
src = transport:source(),
sport = protocol.sport,
dst = transport:destination(),
dport = protocol.dport,
id = dns.id,
qname = label.tooffstr(dns, labels, 16),
qtype = dns.type_tostring(q.type)
})
end
end
end
end
end
print("src", "dst", "id", "rcode", "qname", "qtype")
local q, r
for _, q in pairs(queries) do
for _, r in pairs(responses) do
if q.id == r.id and q.sport == r.dport and q.dport == r.sport and q.src == r.dst and q.dst == r.src then
print(q.src, q.dst, q.id, r.rcode, q.qname, q.qtype)
end
end
end
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