1# -*- coding: utf-8 -*- 2''' 3 calc.py: DNS-based calculator 4 5 Copyright (c) 2009, Zdenek Vasicek (vasicek AT fit.vutbr.cz) 6 Marek Vavrusa (xvavru00 AT stud.fit.vutbr.cz) 7 8 This software is open source. 9 10 Redistribution and use in source and binary forms, with or without 11 modification, are permitted provided that the following conditions 12 are met: 13 14 * Redistributions of source code must retain the above copyright notice, 15 this list of conditions and the following disclaimer. 16 17 * Redistributions in binary form must reproduce the above copyright notice, 18 this list of conditions and the following disclaimer in the documentation 19 and/or other materials provided with the distribution. 20 21 * Neither the name of the organization nor the names of its 22 contributors may be used to endorse or promote products derived from this 23 software without specific prior written permission. 24 25 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 26 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE 29 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 POSSIBILITY OF SUCH DAMAGE. 36''' 37 38#Try: dig @localhost 1*25._calc_.cz. 39 40def init(id, cfg): return True 41def deinit(id): return True 42def inform_super(id, qstate, superqstate, qdata): return True 43 44def operate(id, event, qstate, qdata): 45 46 if (event == MODULE_EVENT_NEW) or (event == MODULE_EVENT_PASS): 47 48 if qstate.qinfo.qname_str.endswith("._calc_.cz.") and not ("__" in qstate.qinfo.qname_str): 49 try: 50 # the second and third argument to eval attempt to restrict 51 # functions and variables available to stop code execution 52 # but it may not be safe either. This is why __ substrings 53 # are excluded from evaluation. 54 res = eval(''.join(qstate.qinfo.qname_list[0:-3]),{"__builtins__":None},{}) 55 except: 56 res = "exception" 57 58 msg = DNSMessage(qstate.qinfo.qname_str, RR_TYPE_TXT, RR_CLASS_IN, PKT_QR | PKT_RA | PKT_AA) #, 300) 59 msg.answer.append("%s 300 IN TXT \"%s\"" % (qstate.qinfo.qname_str,res)) 60 if not msg.set_return_msg(qstate): 61 qstate.ext_state[id] = MODULE_ERROR 62 return True 63 64 qstate.return_rcode = RCODE_NOERROR 65 qstate.ext_state[id] = MODULE_FINISHED 66 return True 67 68 else: 69 #Pass on the unknown query to the iterator 70 qstate.ext_state[id] = MODULE_WAIT_MODULE 71 return True 72 73 elif event == MODULE_EVENT_MODDONE: 74 #the iterator has finished 75 qstate.ext_state[id] = MODULE_FINISHED 76 return True 77 78 log_err("pythonmod: Unknown event") 79 qstate.ext_state[id] = MODULE_ERROR 80 return True 81 82