Correct NATPMP external address resposne epoch and result parsing

spec/lib/rex/proto/natpmp/packet_spec.rb

@@ -0,0 +1,34 @@
+# -*- coding: binary -*-
+require 'spec_helper'
+
+require 'rex/proto/natpmp/packet'
+describe Rex::Proto::NATPMP do
+  subject do
+    mod = Module.new
+    mod.extend described_class
+    mod
+  end
+
+  describe '#parse_external_address_response' do
+    it 'should properly parse non-error responses' do
+      data = "\x00\x80\x00\x00\x00\x33\x50\x53\xc0\xa8\x01\x02"
+      subject.parse_external_address_response(data)
+      ver, opcode, result, epoch, addr = subject.parse_external_address_response(data)
+      expect(ver).to eq(0)
+      expect(opcode).to eq(128)
+      expect(result).to eq(0)
+      expect(epoch).to eq(3362899)
+      expect(addr).to eq('192.168.1.2')
+    end
+    it 'should properly parse error responses' do
+      data = "\x00\x80\x00\x03\x00\x00\x70\x90\x00\x00\x00\x00"
+      subject.parse_external_address_response(data)
+      ver, opcode, result, epoch, addr = subject.parse_external_address_response(data)
+      expect(ver).to eq(0)
+      expect(opcode).to eq(128)
+      expect(result).to eq(3)
+      expect(epoch).to eq(28816)
+      expect(addr).to eq('0.0.0.0')
+    end
+  end
+end